Processes for enhancing flame retardance and chemical resistance of polymers

ABSTRACT

Processes for increasing the chemical resistance of a surface of a formed article are disclosed. The formed article is produced from a polymeric composition comprising a photoactive additive containing photoactive groups derived from a monofunctional benzophenone. The surface of the formed article is then exposed to ultraviolet light to cause crosslinking of the photoactive additive and produce a crosslinked surface. The crosslinking enhances the chemical resistance of the surface. Various means for controlling the depth of the crosslinking are also discussed.

This application is a divisional of U.S. patent application Ser. No.14/137,532, filed Dec. 20, 2013, which claimed priority to U.S.Provisional Patent Application Ser. No. 61/740,062, filed Dec. 20, 2012;to U.S. Provisional Patent Application Ser. No. 61/793,072, filed Mar.15, 2013; to U.S. Provisional Patent Application Ser. No. 61/792,637,filed Mar. 15, 2013; and to U.S. Provisional Patent Application Ser. No.61/901,595, filed Nov. 8, 2013. The disclosure of each application ishereby fully incorporated by reference herein.

BACKGROUND

The present disclosure relates to additives that can be used tocrosslink polymers, such as polycarbonate polymers, for improvedproperties. Also included are compositions including such additives, aswell as articles (e.g. sheets, films, molded components, etc.) formedfrom such compositions. Further discussed herein are processes forincreasing the chemical resistance of the surface of such formedarticles.

Polycarbonates (PC) are synthetic engineering thermoplastic resins, andare a useful class of polymers having many beneficial properties. Theyare useful for forming a wide variety of products, such as by molding,extrusion, and thermoforming processes. Polycarbonate resins are bothstrong and transparent, and are used for a number of differentcommercial applications, including electronic engineering (E&E) parts,mechanical parts, etc. Because of their broad use, particularly inelectronic applications and auto part applications, the desiredproperties of polycarbonates include high impact strength and toughness,heat resistance, weather and ozone resistance, and good ductility.

Polycarbonate polymers/resins, blends containing polycarbonate polymers,and articles formed therefrom exhibit flame retardance properties.However, such polymers drip when exposed to a flame, and this behaviorworsens as the wall thickness decreases. This behavior greatlydiminishes their use in transparent and opaque thin wall applicationswhere a V0 or 5VA flame retardance rating is required. These polymersalso have relatively poor chemical resistance and thus produce articleshaving similar chemical resistance. Consequently, it would be desirableto provide processes that can improve these properties.

BRIEF DESCRIPTION

The present disclosure relates to processes for increasing the chemicalresistance of the surface of an article. The article is formed from apolymeric composition or blend which has improved crosslinkingproperties. The polymeric composition includes a photoactive additivewhich can be used to crosslink resins (e.g. polycarbonates) and improvetheir flame resistance and chemical resistance. The additives are formedby the reaction of at least a first photoactive moiety with a firstlinker moiety. The additive can be a compound, oligomer, or polymer.When exposed to ultraviolet light, crosslinking will occur between thephotoactive additive and other polymeric base resins present in thepolymeric composition, enhancing the chemical resistance of theresulting formed article.

Disclosed in various embodiments are methods for preparing an articlethat has a high probability of passing a UL94 V1 test, comprising: (a)designing a polymeric composition to be exposed to a designed dosage (D)of UV radiation, wherein the polymeric composition comprises: (i) across-linkable polycarbonate resin having endcaps derived from4-monohydroxybenzophenone and a weight average molecular weight of15,000 to 30,000, and (ii) optionally one or more polymeric base resins,and wherein the polymeric composition has a designed weight percentageof the endcaps derived from 4-monohydroxybenzophenone (HBP), a designedmelt flow rate (MF) and a designed weight average molecular weight (MW);(b) preparing the cross-linkable polycarbonate resin by interfacialpolymerization; (c) optionally blending the cross-linkable polycarbonateresin with the optional one or more polymeric base resins to form thepolymeric composition; (d) forming an article from the polymericcomposition; and (e) exposing the formed article to the designed UVdosage; wherein D, HBP, MF, and MW are selected based on an flameperformance equation (Eqn 1) as detailed further herein, which definesthe probability of a first time pass, i.e. p(FTP), in a UL94 V1 test at1.2 mm thickness after UV exposure and after 7 days of aging at 70° C.The p(FTP) is 0.7 or greater; D is at least 12 J/cm² of UVA radiation;and MF is from 7 to 20 g/10 min measured at 300° C./1.2 kg/360 secdwell.

In specific embodiments, the UV radiation is filtered to provide atleast 12 J/cm² of UVA radiation and no detectable UVC radiation, asmeasured using an EIT PowerPuck. In other embodiments, the UV radiationis unfiltered and provides at least 12 J/cm² of UVA radiation and and atleast 0.45 J/cm² of UVC radiation, as measured using an EIT PowerPuck.

Sometimes, D, HBP, MF, and MW are also selected based on a percentageretention of tensile elongation equation (Eqn 3) as detailed furtherherein, which defines the percentage retention of tensile elongation(ER) after exposure to acetone at a thickness of 3.2 mm; wherein the UVradiation is provided by a UV light source that provides at least 12J/cm² of UVA radiation and 0.45 J/cm² UVC radiation, as measured usingan EIT PowerPuck (e.g. an unfiltered D-bulb). ER is 85% or higher.

Sometimes, D and MF are also selected based on a Delta YI equation (Eqn2) as detailed further herein, which defines the Delta YI after exposureto at least 12 J/cm² of UVA radiation and at least 0.45 J/cm² of UVCradiation at 3.2 mm thickness, measured before UV exposure and at least48 hours after UV exposure; wherein the UV radiation is provided by a UVlight source that provides at least 12 J/cm² of UVA radiation and 0.45J/cm² UVC radiation, as measured using an EIT PowerPuck (e.g. anunfiltered D-bulb). The delta YI is 15 or less, and can also be 10 orless, or 8 or less.

Other times, D, HBP, MF, and MW are also selected based on a percentageretention of tensile elongation equation (Eqn 5) as detailed furtherherein, which defines the percentage retention of tensile elongation(ER) after exposure to acetone at a thickness of 3.2 mm; wherein the UVradiation is provided by a filtered UV light source that provides atleast 12 J/cm² of UVA radiation and no detectable UVC radiation, asmeasured using an EIT PowerPuck. ER is 85% or higher.

Still in other variations, D and MF are also selected based on a DeltaYI equation (Eqn 4) as detailed further herein, which defines the DeltaYI after exposure to at least 12 J/cm² of UVA radiation and nodetectable UVC radiation at 3.2 mm thickness, measured before UVexposure and at least 48 hours after UV exposure; wherein the UVradiation is provided by a filtered UV light source that provides atleast 12 J/cm² of UVA radiation and no detectable UVC radiation, asmeasured using an EIT PowerPuck. The delta YI is 15 or less, and canalso be 10 or less, or 8 or less.

In additional embodiments, MW can be from 15,000 to 30,000.Alternatively, HBP can be from 1.2 wt % to 4 wt %.

The polymeric composition may comprise a polymeric base resin, where thepolymeric base resin is a polycarbonate resin that does not containphotoactive groups. The weight ratio of the cross-linkable polycarbonateresin to the polymeric base resin can be from about 50:50 to about85:15. Also disclosed herein are polymeric compositions prepared by themethods described above.

Also disclosed in various embodiments are methods for preparing anarticle that has a low delta YI after exposure to unfiltered UVradiation, comprising: (a) designing a polymeric composition to beexposed to a designed dosage (D) of unfiltered UV radiation, wherein thepolymeric composition comprises: (i) a cross-linkable polycarbonateresin having endcaps derived from 4-monohydroxybenzophenone and a weightaverage molecular weight of 15,000 to 30,000, and (ii) optionally one ormore polymeric base resins, and wherein the polymeric composition has adesigned weight percentage of the endcaps derived from4-monohydroxybenzophenone (HBP), a designed melt flow rate (MF) and adesigned weight average molecular weight (MW); (b) preparing thecross-linkable polycarbonate resin by interfacial polymerization; (c)optionally blending the cross-linkable polycarbonate resin with theoptional one or more polymeric base resins to form the polymericcomposition; (d) forming an article from the polymeric composition; and(e) exposing the formed article to the designed UV dosage; wherein D andMF are selected based on a Delta YI equation (Eqn 2) as detailed furtherherein. The delta YI is 15 or less.

In more specific embodiments, D, HBP, MF, and MW are also selected basedon a retention of tensile elongation equation (Eqn 3) that defines thepercentage retention of tensile elongation (ER), and ER is 85% orhigher.

The delta YI can be 10 or less, or 8 or less. MF may be from 7 to 20g/10 min measured at 300° C./1.2 kg/360 sec dwell. MW may be from 15,000to 30,000. HBP can be from 1.2 wt % to 4 wt %.

The polymeric composition may comprise a polymeric base resin, where thepolymeric base resin is a polycarbonate resin that does not containphotoactive groups. The weight ratio of the cross-linkable polycarbonateresin to the polymeric base resin can be from about 50:50 to about85:15. Also disclosed herein are polymeric compositions prepared by themethods described above.

The present disclosure also describes various embodiments of methods forpreparing an article that has a high percentage of retention of tensileelongation after exposure to acetone at a thickness of 3.2 mm,comprising: (a) designing a polymeric composition to be exposed to adesigned dosage (D) of unfiltered UV radiation, wherein the polymericcomposition comprises: (i) a cross-linkable polycarbonate resin havingendcaps derived from 4-monohydroxybenzophenone and a weight averagemolecular weight of 15,000 to 30,000, and (ii) optionally one or morepolymeric base resins, and wherein the polymeric composition has adesigned weight percentage of the endcaps derived from4-monohydroxybenzophenone (HBP), a designed melt flow rate (MF) and adesigned weight average molecular weight (MW); (b) preparing thecross-linkable polycarbonate resin by interfacial polymerization; (c)optionally blending the cross-linkable polycarbonate resin with theoptional one or more polymeric base resins to form the polymericcomposition; (d) forming an article from the polymeric composition; and(e) exposing the formed article to the designed UV dosage; wherein D,HBP, MF, and MW are selected based on a percentage retention of tensileelongation equation (Eqn 3) that defines the percentage retention oftensile elongation (ER), and ER is 85% or higher. The unfiltered UVradiation provides at least 12 J/cm² of UVA radiation and at least 0.45J/cm² of UVC radiation, and for example can be a D-bulb.

D and MF can also be selected based on a Delta YI equation (Eqn 2) asdetailed further herein, where the delta YI is 15 or less, or 10 orless, or 8 or less.

MF may be from 7 to 20 g/10 min measured at 300° C./1.2 kg/360 secdwell. MW may be from 15,000 to 30,000. HBP can be from 1.2 wt % to 4 wt%.

The polymeric composition may comprise a polymeric base resin, where thepolymeric base resin is a polycarbonate resin that does not containphotoactive groups. The weight ratio of the cross-linkable polycarbonateresin to the polymeric base resin can be from about 50:50 to about85:15. Also disclosed herein are polymeric compositions prepared by themethods described above.

Disclosed in various embodiments are methods for preparing an articlethat has a low delta YI after exposure to filtered UV radiation,comprising: (a) designing a polymeric composition to be exposed to adesigned dosage (D) of filtered UV radiation, wherein the polymericcomposition comprises: (i) a cross-linkable polycarbonate resin havingendcaps derived from 4-monohydroxybenzophenone and a weight averagemolecular weight of 15,000 to 30,000, and (ii) optionally one or morepolymeric base resins, and wherein the polymeric composition has adesigned weight percentage of the endcaps derived from4-monohydroxybenzophenone (HBP), a designed melt flow rate (MF) and adesigned weight average molecular weight (MW); (b) preparing thecross-linkable polycarbonate resin by interfacial polymerization; (c)optionally blending the cross-linkable polycarbonate resin with theoptional one or more polymeric base resins to form the polymericcomposition; (d) forming an article from the polymeric composition; and(e) exposing the formed article to the designed UV dosage; wherein D andMF are selected based on a Delta YI equation (Eqn 4) as detailed furtherherein. the UV radiation is provided by a filtered UV light source thatprovides at least 12 J/cm² of UVA radiation and no detectable UVCradiation, as measured using an EIT PowerPuck. The delta YI is 15 orless, and can also be 10 or less, or 8 or less.

In more specific embodiments, D, HBP, MF, and MW are also selected basedon a retention of tensile elongation equation (Eqn 5) that defines thepercentage retention of tensile elongation (ER), and ER is 85% orhigher.

MF may be from 7 to 20 g/10 min measured at 300° C./1.2 kg/360 secdwell. MW may be from 15,000 to 30,000. HBP can be from 1.2 wt % to 4 wt%.

The polymeric composition may comprise a polymeric base resin, where thepolymeric base resin is a polycarbonate resin that does not containphotoactive groups. The weight ratio of the cross-linkable polycarbonateresin to the polymeric base resin can be from about 50:50 to about85:15. Also disclosed herein are polymeric compositions prepared by themethods described above.

Disclosed in various embodiments are methods for preparing an articlethat has a high percentage of retention of tensile elongation afterexposure to acetone at a thickness of 3.2 mm, comprising: (a) designinga polymeric composition to be exposed to a designed dosage (D) offiltered UV radiation, wherein the polymeric composition comprises: (i)a cross-linkable polycarbonate resin having endcaps derived from4-monohydroxybenzophenone and a weight average molecular weight of15,000 to 30,000, and (ii) optionally one or more polymeric base resins,and wherein the polymeric composition has a designed weight percentageof the endcaps derived from 4-monohydroxybenzophenone (HBP), a designedmelt flow rate (MF) and a designed weight average molecular weight (MW);(b) preparing the cross-linkable polycarbonate resin by interfacialpolymerization; (c) optionally blending the cross-linkable polycarbonateresin with the optional one or more polymeric base resins to form thepolymeric composition; (d) forming an article from the polymericcomposition; and (e) exposing the formed article to the designed UVdosage; wherein D, HBP, MF, and MW are selected based on a percentageretention of tensile elongation equation (Eqn 5) that defines thepercentage retention of tensile elongation (ER), and ER is 85% orhigher. The UV radiation is provided by a filtered UV light source thatprovides at least 12 J/cm² of UVA radiation and no detectable UVCradiation, as measured using an EIT PowerPuck.

D and MF can also be selected based on a Delta YI equation (Eqn 4) asdetailed further herein, where the delta YI is 15 or less, or 10 orless, or 8 or less.

MF may be from 7 to 20 g/10 min measured at 300° C./1.2 kg/360 secdwell. MW may be from 15,000 to 30,000. HBP can be from 1.2 wt % to 4 wt%.

The polymeric composition may comprise a polymeric base resin, where thepolymeric base resin is a polycarbonate resin that does not containphotoactive groups. The weight ratio of the cross-linkable polycarbonateresin to the polymeric base resin can be from about 50:50 to about85:15. Also disclosed herein are polymeric compositions prepared by themethods described above.

Disclosed in various embodiments herein are processes for enhancing thechemical resistance of a surface of an article, comprising: forming thearticle with a polymeric composition comprising a photoactive additive;and exposing the surface of the formed article to a selected ultravioletlight range at an effective dosage to cause crosslinking of thephotoactive additive and produce a crosslinked surface.

The crosslinked polymer may have a depth of at least 10 micrometers, orat least 35 micrometers, from the UV-exposed surface.

In some embodiments, the selected ultraviolet light range is from about330 nm to about 380 nm, or is from about 280 nm to about 360 nm, or isfrom about 330 nm to about 360 nm.

Sometimes, the crosslinked surface has a delta YI after 48 hours of 4 orless, the YI being measured on a 1.6 mm bar after at least 48 hours at23° C. in the dark.

In other embodiments, the total UV energy received by the surface fromUVA, UVB, and UVC light is about 45 J/cm².

The polymeric composition may further comprise a polymeric base resin.In particular embodiments, the polymeric base resin has a weight averagemolecular weight of 21,000 or greater. The polymeric composition maycomprise from 1 wt % to 99 wt % of the polymeric base resin and from 1wt % to 99 wt % of the photoactive additive. More specifically, thepolymeric base resin can be a polycarbonate.

The photoactive additive can be formed from the reaction of: a firstphotoactive moiety comprising a ketone group and only one functionalgroup; and a first linker moiety comprising a plurality of linkinggroups, wherein each linking group reacts with the functional group ofthe first photoactive moiety; and a chain extender.

The photoactive additive may have a weight average molecular weight of15,000 or greater.

In particular embodiments, the photoactive additive may be across-linkable polycarbonate resin having the structure of Formula (I)or Formula (II), as more fully described herein. The cross-linkablepolycarbonate resin may have a weight-average molecular weight from17,000 to 80,000 Daltons, as measured by GPC using a UV detector andpolycarbonate standards. The cross-linkable polycarbonate resin can havea polydispersity index (PDI) of between 3.0 and 7.3 as measured by GPCusing a UV detector and polycarbonate standards. The ratio of thepolydispersity index (PDI) measured using a UV detector to the PDImeasured using an RI detector may be 1.8 or less, when using a GPCmethod and polycarbonate molecular weight standards. In particularembodiments, the cross-linkable polycarbonate resin has a melt volumeflow rate of about 2 to about 12 cc/10 min at 300° C./1.2 kg/360 secdwell.

A plaque comprising the polymeric composition can have a transparency of70% or greater at a thickness of 3.2 mm, measured according toASTM-D1003-00. A plaque comprising the polymeric composition can have ahaze value of less than 2% at a thickness of 2.54 mm, measured accordingto ASTM D1003-07.

The polymeric composition may further comprise a flame retardant.Sometimes, the flame retardant is potassium perfluorobutane sulfonate(Rimar salt), potassium diphenyl sulfone-3-sulfonate (KSS), or acombination thereof. In particular embodiments, the flame retardant isRimar salt which is present in an amount of about 0.05 wt % to about0.085 wt %, based on the total weight of the composition, and the plaquecomprising the polymeric composition has a transparency of 70 to 90% ata thickness of 3.2 mm, measured according to ASTM-D1003-00. Inparticular embodiments, the polymeric composition further comprises aheat stabilizer and a mold release agent.

Also disclosed are articles formed from the processes described herein.Such articles may include a film, a sheet, a layer of a multilayer film,or a layer of a multilayer sheet. The article can be formed by injectionmolding, overmolding, co-injection molding, extrusion, multilayerextrusion, rotational molding, blow molding, or thermoforming.

Also disclosed herein are compositions, comprising: a cross-linkablepolycarbonate resin having endcaps derived from amonohydroxybenzophenone and a weight average molecular weight (Mw) from15,000 to 30,000 and a PDI from 3.0 to 4.0 as measured by GPC using a UVdetector and polycarbonate standards; optionally one or more additionalpolycarbonate base resins different from the cross-linkablepolycarbonate resin; and a flame retardant; wherein the compositioncomprises at least 45 wt % of the polycarbonate cross-linkablepolycarbonate resin, wherein the monohydroxybenzophenone-derived endcapcontent of the composition is between 1.2 wt % and 4 wt %, wherein thecomposition has a melt flow rate (MFR) of 7 to 20 g/10 min measured at300° C./1.2 kg/360 sec dwell, and wherein an article formed from thecomposition has a % T of 85% or greater at 3.2 mm thickness.

Also disclosed are molded articles formed from such compositions,wherein after irradiation with UV light, the article has (a) a % T of75% or greater at 3.2 mm thickness, and (b) either (i) a gel layer of atleast 8 microns thickness as measured by optical microscopy; or (ii) anincrease in Mw of at least 30% as measured by GPC using a UV detectorand polycarbonate standards.

The molded article can also have a pFTP(V1) of at least 0.95 at 1.2 mmthickness after aging for 7 days at 70° C. The molded article could alsohave a delta YI value of 12 or less at 3.2 mm thickness measured atleast 48 hours after UV exposure. Sometimes, the molded article has apFTP(V0) of at least 0.6 at 1.2 mm thickness.

In particular embodiments, the molded article has a % retention of 85%or greater at 3.2 mm thickness in a tensile elongation at break testusing the ASTM D638 Type I method at 50 mm/min after exposure to acetoneunder 1% strain at 23° C. In addition, the molded article can have adelta YI of less than 12 at 3.2 mm thickness measured at least 48 hoursafter UV exposure, and/or can have a pFTP(V1) of at least 0.95 at 1.2 mmthickness after aging for 7 days at 70° C.

Other times, the molded article also has a % retention of 90% or greaterat 3.2 mm thickness in a tensile elongation at break test using the ASTMD638 Type I method at 50 mm/min after exposure to acetone under 1%strain at 23° C. In addition, the molded article can have a delta YI ofless than 12 at 3.2 mm thickness measured at least 48 hours after UVexposure, and/or a pFTP(V1) of at least 0.95 at 1.2 mm thickness afteraging for 7 days at 70° C.

Additionally disclosed herein in different embodiments are methods forforming a cross-linked polycarbonate article, comprising: receiving acomposition that comprises: a cross-linkable polycarbonate resin havingendcaps derived from a monohydroxybenzophenone, a weight averagemolecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 asmeasured by GPC using a UV detector and polycarbonate standards, and amonohydroxybenzophenone-derived endcap content from 3.0 to 4.5 wt %;optionally one or more additional polycarbonate base resins differentfrom the cross-linkable polycarbonate resin; and a flame retardant;wherein the monohydroxybenzophenone-derived endcap content of thecomposition is between 1.2 wt % and 4 wt %, and wherein the compositionhas a melt flow rate (MFR) of 7 to 20 g/10 min measured at 300° C./1.2kg/360 sec dwell; forming an article from the composition; and exposingthe formed article to UV radiation from a UV radiation source for a timesufficient to form the cross-linked polycarbonate article; wherein thecross-linked polycarbonate article has a gel layer of at least 5 micronsthickness as measured by optical microscopy, and wherein the moldedarticle after exposure to UV radiation has a pFTP(V1) of at least 0.95at 1.2 mm thickness after aging for 7 days at 70° C.

The UV radiation source can be a metal halide doped mercury lamp, anelectrodeless D-bulb, an electrodeless H-bulb, an electrodeless V-bulb,a Xenon Arc lamp, or a UVA (320-390 nm) light emitting diode (LED). Inspecific embodiments, the UV radiation source is a metal halide dopedmercury lamp or an electrodeless D-bulb.

Sometimes, the molded article is exposed to UV radiation from a metalhalide doped mercury lamp providing at least 12 J/cm² of UVA as measuredusing an EIT PowerPuck. In other variations, the molded article isexposed to UV radiation from a metal halide doped mercury lamp providingat least 35.9 J/cm² of UVA as measured using an EIT PowerPuck. Themolded article can be exposed to UV radiation from a metal halide dopedmercury lamp providing at least 59.9 J/cm² of UVA as measured using anEIT PowerPuck. The article can be formed by injection molding.

In particular embodiments, the molded article is exposed to filtered UVradiation using a 280 nm long pass filter. In other embodiments, themolded article is exposed to filtered UV radiation using a 320 nm longpass filter.

Also disclosed are methods for preparing an injection-molded articlehaving low yellowness and high chemical resistance, comprising:receiving a composition that comprises: a cross-linkable polycarbonateresin having endcaps derived from a monohydroxybenzophenone, a weightaverage molecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0to 4.0 as measured by GPC using a UV detector and polycarbonatestandards, and a monohydroxybenzophenone-derived endcap content from 3.0to 4.5 wt %; optionally one or more additional polycarbonate base resinsdifferent from the cross-linkable polycarbonate resin; and optionally aflame retardant; wherein the composition has a melt flow rate (MFR) of 7g/10 min or higher, measured at 300° C./1.2 kg/360 sec dwell;injection-molding the composition to a molded article; and exposing themolded article to a selected UV light range and a selected dosage of UVradiation to obtain the injection-molded article, wherein the injectionmolded article has a YI of 15 or less at 3.2 mm thickness and has a %retention of 85% or greater at 3.2 mm thickness in a tensile elongationat break test using the ASTM D638 Type I method at 50 mm/min afterexposure to acetone under 15% strain at 23° C.

The injection molded article can have a pFTP(V1) of at least 0.70 at 1.2mm thickness after aging for 7 days at 70° C. Alternatively, theinjection molded article can have a YI of 8 or less. Sometimes, thecomposition has a melt flow rate (MFR) of 7 to 15 g/10 min.

In particular embodiments, the composition comprises Rimar salt flameretardant, and the injection molded article has a pFTP(V1) of at least0.70 at 1.2 mm thickness after aging for 7 days at 70° C.

In other specific embodiments, the composition comprises Rimar saltflame retardant, and the injection molded article has a pFTP(V1) of atleast 0.90 at 1.2 mm thickness after aging for 7 days at 70° C.

In yet other different embodiments, the composition comprises Rimar saltflame retardant, and the injection molded article has a pFTP(V0) of atleast 0.60 at 1.2 mm thickness after aging for 7 days at 70° C.

Described herein in various embodiments are articles molded from apolycarbonate composition, wherein the polycarbonate compositioncomprises: a cross-linkable polycarbonate resin comprising from 2 to 4wt % of end-caps derived from a monohydroxybenzophenone, and having aweight average molecular weight from 15,000 to 30,000 as measured by GPCusing a UV detector and polycarbonate standards; optionally one or moreadditional polycarbonate base resins different from the cross-linkablepolycarbonate resin; optionally a flame retardant; and optionally acolorant, a UV stabilizer, a thermal stabilizer, or a mold releaseagent; wherein the polycarbonate composition has amonohydroxybenzophenone-derived endcap content from 1.3 wt % to 3.8 wt%, and a melt flow rate (MFR) of 7 to 20 g/10 min measured at 300°C./1.2 kg/360 sec dwell, and wherein a molded part formed from thepolycarbonate composition has a % T of 85% or greater at 3.2 mmthickness; and wherein a part molded from the polycarbonate compositionand exposed to at least 35 J/cm² of UVA radiation has a delta YI of 8 orless at 3.2 mm thickness measured at least 48 hours after exposure, a %T of 75% or greater, a % retention of 85% or greater at 3.2 mm thicknessin a tensile elongation at break test using the ASTM D638 Type I methodat 50 mm/min after exposure to acetone under 1.0% strain at 23° C., anda pFTP(V1) of at least 0.90 at 1.2 mm thickness after aging for 7 daysat 70° C. The polycarbonate composition has in more specific embodimentsa melt flow rate (MFR) of 7 to 15 g/10 min.

These and other non-limiting characteristics are more particularlydescribed below.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a brief description of the drawings, which arepresented for the purposes of illustrating the exemplary embodimentsdisclosed herein and not for the purposes of limiting the same.

FIG. 1 illustrates the formation of a photoactive additive (compound)from a monofunctional photoactive moiety and a first linker moiety.

FIG. 2 illustrates the formation of a photoactive additive(oligomer/polymer) from a monofunctional photoactive moiety, a firstlinker moiety, a diol chain extender, and an endcapping agent.

FIG. 3 illustrates the formation of a photoactive additive from a firstphotoactive moiety, a first linker moiety, and a diol chain extender.

FIG. 4 illustrates the formation of a photoactive additive from a firstphotoactive moiety, a first linker moiety, and a secondary linkermoiety.

FIG. 5 illustrates the formation of a photoactive additive from a firstphotoactive moiety, a chain extender, a first linker moiety, and asecondary linker moiety.

FIG. 6 illustrates the crosslinking mechanism of the photoactiveadditive.

FIG. 7 is a graph showing the transmission spectra for glass, a LEXANsheet, polycarbonate, noncrosslinked benzophenone-containingpolycarbonate, and a D bulb.

FIG. 8 is a graph showing a correlation between crosslinking andyellowing for a benzophenone-containing polycarbonate.

FIG. 9 is a graph showing a correlation between crosslinking andyellowing for a different benzophenone-containing polycarbonate.

FIG. 10 is a graph comparing the results obtained from two differentmethods of measuring the thickness of the crosslinked skin.

FIG. 11 is a graph showing the crosslinked skin thickness versus the UVdosage as measured by the number of passes through the UV chamber.

FIG. 12 is a graph showing the average gel percentage versus the UVdosages for a sample exposed using a filter versus a sample exposedwithout a filter.

FIG. 13 is a graph showing the delta YI versus the UV dosage for asample exposed using a filter versus a sample exposed without a filter.

FIG. 14 is a graph showing the transmission spectrum of long passUV-filters. The transmission spectrum is represented by plottinginternal transmittance versus UV light wavelength.

FIG. 15 is a graph showing the thickness of cross-linked polycarbonatelayers versus the number of passes through a UV chamber with and withoutUV filters.

FIG. 16 is a graph showing the shift in yellowness versus the thicknessof cross-linked polycarbonate layers with and without UV filters.

FIG. 17 depicts polycarbonate composition molecular weight as a functionof UV-exposure.

FIG. 18 depicts the molecular weight build (%) as a function of4-hydroxybenzophenone endcap content in polycarbonate compositionstreated with UV-radiation.

FIG. 19 depicts overlayed NMR spectra demonstrating peak intensityincrease at 3.48 ppm showing progression of polycarbonate cross-linking.

FIG. 20 depicts NMR peak intensity at 3.48 ppm as a function ofUV-treatment of 4-hydroxybenzophenone endcapped polycarbonates.

FIG. 21 depicts polycarbonate composition molecular weight as a functionof sun exposure time.

FIG. 22 depicts small amplitude oscillatory rheology [parallel-plate] ofa low-flow BPA-polycarbonate resin.

FIG. 23 depicts small amplitude oscillatory rheology [parallel-plate] ofa low-flow benzophenone endcapped BPA-polycarbonate copolymer resin.

FIG. 24 is a chart showing the predicted p(FTP) for samples aged 7 daysand tested for V1 when applying the model equation for flame performanceand holding the MFR constant at a low value.

FIG. 25 is a second chart showing the predicted p(FTP) when applying themodel equation for flame performance and holding the MFR constant at ahigher value.

FIG. 26 is a chart showing the predicted retention of elongation atbreak following acetone testing when applying the model equation for theretention of tensile elongation using a filtered bulb with the HBPcontent held constant.

FIG. 27 is another chart showing the model equation for the retention oftensile elongation using a filtered bulb with the HBP content heldconstant at a higher value.

FIG. 28 is a chart that illustrates the combination of three modelequations to find a design space.

DETAILED DESCRIPTION

The present disclosure may be understood more readily by reference tothe following detailed description of desired embodiments and theexamples included therein. In the following specification and the claimswhich follow, reference will be made to a number of terms which shall bedefined to have the following meanings.

Definitions

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art. In case of conflict, the present document, includingdefinitions, will control. Preferred methods and materials are describedbelow, although methods and materials similar or equivalent to thosedescribed herein can be used in practice or testing of the presentinvention. All publications, patent applications, patents and otherreferences mentioned herein are incorporated by reference in theirentirety. The materials, methods, and examples disclosed herein areillustrative only and not intended to be limiting.

The singular forms “a,” “an,” and “the” include plural referents unlessthe context clearly dictates otherwise.

As used in the specification and in the claims, the term “comprising”may include the embodiments “consisting of” and “consisting essentiallyof.” The terms “comprise(s),” “include(s),” “having,” “has,” “can,”“contain(s),” and variants thereof, as used herein, are intended to beopen-ended transitional phrases, terms, or words that do not precludethe possibility of additional acts or structures.

Numerical values in the specification and claims of this application,particularly as they relate to polymers or polymer compositions, reflectaverage values for a composition that may contain individual polymers ofdifferent characteristics. Furthermore, unless indicated to thecontrary, the numerical values should be understood to include numericalvalues which are the same when reduced to the same number of significantfigures and numerical values which differ from the stated value by lessthan the experimental error of conventional measurement technique of thetype described in the present application to determine the value.

All ranges disclosed herein are inclusive of the recited endpoint andindependently combinable (for example, the range of “from 2 grams to 10grams” is inclusive of the endpoints, 2 grams and 10 grams, and all theintermediate values). The endpoints of the ranges and any valuesdisclosed herein are not limited to the precise range or value; they aresufficiently imprecise to include values approximating these rangesand/or values.

As used herein, approximating language may be applied to modify anyquantitative representation that may vary without resulting in a changein the basic function to which it is related. Accordingly, a valuemodified by a term or terms, such as “about” and “substantially,” maynot be limited to the precise value specified, in some cases. In atleast some instances, the approximating language may correspond to theprecision of an instrument for measuring the value. The modifier “about”should also be considered as disclosing the range defined by theabsolute values of the two endpoints. For example, the expression “fromabout 2 to about 4” also discloses the range “from 2 to 4.” The term“about” may refer to plus or minus 10% of the indicated number. Forexample, “about 10%” may indicate a range of 9% to 11%, and “about 1”may mean from 0.9-1.1. Other meanings of “about” may be apparent fromthe context, such as rounding off, so, for example “about 1” may alsomean from 0.5 to 1.4.

For the recitation of numeric ranges herein, each intervening numberthere between with the same degree of precision is explicitlycontemplated. For example, for the range of 6-9, the numbers 7 and 8 arecontemplated in addition to 6 and 9, and for the range 6.0-7.0, thenumber 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, and 7.0 areexplicitly contemplated.

Compounds are described using standard nomenclature. For example, anyposition not substituted by any indicated group is understood to haveits valency filled by a bond as indicated, or a hydrogen atom. A dash(“-”) that is not between two letters or symbols is used to indicate apoint of attachment for a substituent. For example, the aldehyde group—CHO is attached through the carbon of the carbonyl group.

The term “aliphatic” refers to an linear or branched array of atoms thatis not aromatic. The backbone of an aliphatic group is composedexclusively of carbon. The aliphatic group may be substituted orunsubstituted. Exemplary aliphatic groups include, but are not limitedto, methyl, ethyl, isopropyl, hexyl, and cyclohexyl.

The term “aromatic” refers to a radical having a ring system containinga delocalized conjugated pi system with a number of pi-electrons thatobeys Hückel's Rule. The ring system may include heteroatoms such asnitrogen, sulfur, selenium, silicon and oxygen, or may be composedexclusively of carbon and hydrogen. Aromatic groups are not substituted.Exemplary aromatic groups include, but are not limited to, phenyl,pyridyl, furanyl, thienyl, naphthyl and biphenyl.

The term “ester” refers to a radical of the formula —CO—O—, wherein thecarbon atom and the oxygen atom are both covalently bonded to carbonatoms.

The term “carbonate” refers to a radical of the formula —O—CO—O—,wherein the oxygen atoms are both covalently bonded to carbon atoms.Note that a carbonate group is not an ester group, and an ester group isnot a carbonate group.

The term “hydroxyl” refers to a radical of the formula —OH, wherein theoxygen atom is covalently bonded to a carbon atom.

The terms “carboxy” or “carboxyl” refers to a radical of the formula—COOH, wherein the carbon atom is covalently bonded to another carbonatom. It should be noted that for the purposes of this disclosure, acarboxyl group may be considered as having a hydroxyl group. However, itshould be noted that a carboxyl group can participate in certainreactions differently from a hydroxyl group.

The term “anhydride” refers to a radical of the formula —CO—O—CO—,wherein the carbonyl carbon atoms are covalently bonded to other carbonatoms. An anhydride can be considered as being equivalent to twocarboxyl groups.

The term “acid halide” refers to a radical of the formula —CO—X, whereinthe carbon atom is covalently bonded to another carbon atom.

The term “alkyl” refers to a radical composed entirely of carbon atomsand hydrogen atoms which is fully saturated. The alkyl radical may belinear, branched, or cyclic.

The term “aryl” refers to an aromatic radical that is composedexclusively of carbon and hydrogen. Exemplary aryl groups includephenyl, naphthyl, and biphenyl. Note that “aryl” is a subset ofaromatic.

The term “heteroaryl” refers to an aromatic radical having a ring systemthat is composed of carbon, hydrogen, and at least one heteroatom.Exemplary heteroaryl groups include pyridyl, furanyl, and thienyl. Notethat “heteroaryl” is a subset of aromatic, and is exclusive of “aryl”.

The term “halogen” refers to fluorine, chlorine, bromine, and iodine.

The term “alkoxy” refers to an alkyl radical which is attached to anoxygen atom, i.e. —O—C_(n)H_(2n+1).

The term “aryloxy” refers to an aryl radical which is attached to anoxygen atom, e.g. —O—C₆H₅.

The term “hydrocarbon” refers to a radical which is composed exclusivelyof carbon and hydrogen. Both alkyl and aryl groups are consideredhydrocarbon groups.

The term “alkenyl” refers to a radical composed entirely of carbon atomsand hydrogen atoms which contains at least one carbon-carbon double bondthat is not part of an aryl or heteroaryl structure. The alkenyl radicalmay be linear, branched, or cyclic. An exemplary alkenyl radical isvinyl (—CH═CH₂).

The term “alkenyloxy” refers to a alkenyl radical which is attached toan oxygen atom, e.g. —O—CH═CH₂.

The term “arylalkyl” refers to an aryl radical which is attached to analkyl radical, with the aryl radical being appended to the parentmolecular moiety through the alkyl radical, e.g. benzyl (—CH₂—C₆H₅).

The term “alkylaryl” refers to an alkyl radical which is attached to anaryl radical, with the alkyl radical being appended to the parentmolecular moiety through the aryl radical, e.g. tolyl (—C₆H₄—CH₃).

The term “amino” refers to a radical of the formula R—NH₂, wherein R isa carbon atom. For purposes of this disclosure, the amino group is aprimary amino group, i.e. contains two hydrogen atoms.

The term “ureido” refers to a radical of the formula —NH—CO—NH—, whereinthe nitrogen atoms are both covalently bonded to carbon atoms.

The term “carbamate” refers to a radical of the formula —NH—CO—O—,wherein the nitrogen atom and the oxygen atom are both covalently bondedto carbon atoms.

The term “amide” refers to a radical of the formula —CO—NH—, wherein thenitrogen atom and the carbon atom are both covalently bonded to carbonatoms.

The term “copolymer” refers to a polymer derived from two or morestructural unit or monomeric species, as opposed to a homopolymer, whichis derived from only one structural unit or monomer.

The term “C₃-C₆ cycloalkyl” refers to cyclopropyl, cyclobutyl,cyclopentyl or cyclohexyl.

The terms “Glass Transition Temperature” or “Tg” refer to the maximumtemperature that a polymer, such as a polycarbonate, will have one ormore useful properties. These properties include impact resistance,stiffness, strength, and shape retention. The Tg of a polycarbonatetherefore may be an indicator of its useful upper temperature limit,particularly in plastics applications. The Tg may be measured using adifferential scanning calorimetry method and expressed in degreesCelsius.

The glass transition temperature of a polymer, such as a polycarbonate,may depend primarily on the composition of the polymer. Polycarbonatesthat are formed from monomers having more rigid and less flexiblechemical structures than Bisphenol-A generally have higher glasstransition temperatures than Bisphenol-A polycarbonate, whilepolycarbonates that are formed from monomers having less rigid and moreflexible chemical structures than Bisphenol-A generally have lower glasstransition temperatures than Bisphenol-A polycarbonate. For example, apolycarbonate formed from 33 mole % of a rigid monomer,3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (“PPPBP”), and 67 mole% Bisphenol-A has a glass transition temperature of 198° C., while apolycarbonate formed from Bisphenol-A, but also having 6 wt % ofsiloxane units, a flexible monomer, has a glass transition temperatureof 145° C.

Mixing of two or more polycarbonates having different glass transitiontemperatures may result in a glass transition temperature value for themixture that is intermediate between the glass transition temperaturesof the polycarbonates that are mixed.

The glass transition temperature of a polycarbonate may also be anindicator of the molding or extrusion temperatures required to formpolycarbonate parts. The higher the glass transition temperature of thepolycarbonate the higher the molding or extrusion temperatures that areneeded to form polycarbonate parts.

The glass transition temperatures (Tg) described herein are measures ofheat resistance of, for example, polycarbonate and polycarbonate blends.The Tg can be determined by differential scanning calorimetry. Thecalorimetry method may use a TA Instruments Q1000 instrument, forexample, with setting of 20° C./min ramp rate and 40° C. starttemperature and 200° C. end temperature.

The term “halo” means that the substituent to which the prefix isattached is substituted with one or more independently selected halogenradicals. For example, “C₁-C₆ haloalkyl” means a C₁-C₆ alkyl substituentwherein one or more hydrogen atoms are replaced with independentlyselected halogen radicals. Non-limiting examples of C₁-C₆ haloalkylinclude chloromethyl, 1-bromoethyl, fluoromethyl, difluoromethyl,trifluoromethyl, and 1,1,1-trifluoroethyl. It should be recognized thatif a substituent is substituted by more than one halogen radical, thosehalogen radicals may be identical or different (unless otherwisestated).

The term “haze” refers to the percentage of transmitted light, which inpassing through a specimen deviates from the incident beam by forwardscattering. Percent (%) haze may be measured according to ASTM D1003-07.

The term “Melt Volume Rate” (MVR) refers to the flow rate of a polymerin a melt phase as determined using the method of ASTM 1238-10. The MVRof a molten polymer is measured by determining the amount of polymerthat flows through a capillary of a specific temperature over aspecified time using standard weights at a fixed temperature. MVR isexpressed in cubic centimeter per 10 minutes. The higher the MVR valueof a polymer at a specific temperature, the greater the flow of thatpolymer at that specific temperature.

The term “Peak melt viscosity” refers to the highest melt viscosityvalue (in poise) achieved between 350° C. and 450° C. during rheologicaltesting of a polycarbonate resin.

The term “Percent transmission” or “% transmission” refers to the ratioof transmitted light to incident light, and may be measured according toASTM D 1003-07.

“Polycarbonate” as used herein refers to an oligomer or a polymercomprising residues of one or more monomers, joined by carbonatelinkages.

The terms “UVA”, “UVB”, “UVC”, and “UVV” as used herein were defined bythe wavelengths of light measured with the radiometer (EIT PowerPuck)used in these studies, as defined by the manufacturer (EIT Inc.,Sterling, Va.). Other wavelength ranges outside of the measurementranges were considered and include the entire range of UV and near UVwavelengths (200 nm to 450 nm). The combination of these ranges werealso considered and used.

“Thermal stability” as used herein refers to resistance of a polymer tomolecular weight degradation under thermal conditions. Thus, a polymerwith poor thermal stability may show significant molecular weightdegradation under thermal conditions, such as during extrusion, molding,thermoforming, hot-pressing, and like conditions. Molecular weightdegradation may also be manifest through color formation and/or in thedegradation of other properties such as weatherability, gloss,mechanical properties, and/or thermal properties. Molecular weightdegradation can also cause significant variation in processingconditions such as melt viscosity changes.

The present disclosure refers to “polymers,” “oligomers”, and“compounds”. A polymer is a large molecule composed of multiplerepeating units chained together, the repeating units being derived froma monomer. One characteristic of a polymer is that different moleculesof a polymer will have different lengths, and a polymer is described ashaving a molecular weight that is based on the average value of thechains (e.g. weight average or number average molecular weight). The artalso distinguishes between an “oligomer” and a “polymer”, with anoligomer having only a few repeating units, while a polymer has manyrepeating units. For purposes of this disclosure, the term “oligomer”refers to such molecules having a weight average molecular weight ofless than 15,000, and the term “polymer” refers to molecules having aweight average molecular weight of 15,000 of more, as measured by GPCusing polycarbonate molecular weight standards. In contrast, for acompound, all molecules will have the same molecular weight. Compared toa polymer, a compound is a small molecule.

Compositions

The present disclosure relates to photoactive additives (PAA), andprocesses for using such additives to improve chemical resistance at thesurface of an article. When the photoactive additive is added to one ormore base resins and is then exposed to the appropriate wavelength oflight, the resulting composition will have improved anti-drip and flameretardant properties, chemical resistance, transparency, and mechanicalproperties compared to the base resins alone or to the composition priorto the light exposure. For example, the chemical resistance, propensityto drip during burning, or the propensity to form a hole when exposed toa flame can be improved. Improved flame resistance performancecharacteristics may include flame out time (FOT) and time to drip (TTD).The compositions, blended or neat, can be used to provide thin-walledmaterials that are UL94 5VA compliant. The compositions can be used toprovide thin-walled materials that are 5VA compliant and highlytransparent. The compositions may also be used to produce articles thatexhibit good chemical resistance, scratch resistance, tear resistance,impact strength, ductility, hydrolytic stability, and/or weatherability.Compositions comprising a cross-linked polycarbonate formed from the PAAare also contemplated, as well as articles/materials formed therefrom.

Generally, the photoactive additives (PAA) of the present disclosureinclude photoactive moieties that are covalently linked together througha first linker moiety and possibly a secondary linker moiety. Thephotoactive moieties contain a photoactive ketone group that, whenexposed to the appropriate wavelength(s) of light, will form a stablecovalent bond between the PAA and the polymeric resin. The PAA should bestable at conventional blending, forming, and processing temperatures(i.e. stable at 350° C. or above). The PAA also should not induce thedegradation of the polymeric resin with which it is blended.

The term “photoactive moiety” refers to a moiety that, when exposed tolight of the appropriate wavelength, crosslinks with another molecule.Thus, for example, the bisphenol-A monomer in a bisphenol-A homopolymerwould not be considered a photoactive moiety, even though photo-Friesrearrangement can occur upon exposure to light, because the atoms do notparticipate in crosslinking but merely in rearrangement of the polymerbackbone.

The photoactive additive is formed from a reaction mixture containing atleast a first photoactive moiety and a first linker moiety. Thephotoactive moiety comprises (i) a photoactive group and (ii) only onefunctional group. The linker moiety comprises a plurality of linkinggroups that can react with the functional group of the photoactivemoiety. The reaction product is the photoactive additive (PAA). Themolar ratio of the photoactive moiety to the linker moiety can be from1:2 to 20:1. A second end-capping agent may also be included. Asdesired, a chain extender can also be included. The second end-cappingagent and the chain extender do not have photoactive properties.

The term “ketone group” refers to a carbonyl group (—CO—) that is bondedto two other carbon atoms (i.e. —R—CO—R′—). The two other carbon atomscan be in an aliphatic group or in an aromatic group. An ester group anda carboxylic acid group are not considered to be a ketone group becausethe carbonyl group is bonded to one carbon atom and an oxygen atom.

The functional group of the photoactive moiety can be a hydroxyl group,an amino group, or a carboxyl group or equivalent thereof. In thisregard, carboxyl, ester, acid halide, and anhydrides react in the sameway, and are thus considered to be equivalent to each other. Forclarity, these four groups are illustrated below:

wherein R is the remainder of the photoactive moiety, R′ is alkyl oraryl, and X is a halogen. It should be noted that the anhydrideessentially contains two carboxyl groups.

The linking groups of the linker moiety react with the functional groupof the photoactive moiety, and are generally also a hydroxyl group, anamino group, or a carboxyl group or equivalent thereof. In this regard,a hydroxyl group will react with a carboxyl group or its equivalents. Anamino group will react with a carboxyl group or its equivalents. Acarboxyl group or equivalent will react with a hydroxyl group or anamino group, but will not react with another carboxyl (because theanhydride is formed).

In some embodiments, the photoactive moiety can be a benzophenonemoiety. Benzophenone is also known as diphenylketone or benzoyl benzene.A benzophenone moiety is shown below as Formula (0):

In some embodiments, the photoactive moiety contains only one functionalgroup. Examples of such photoactive moieties include those having thestructure of one of Formulas (1)), (3), or (5)-(10):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen; and R is H, alkyl, or aryl.

The compound of Formula (1) is a (Z)benzophenone. The compound ofFormula (3) is a 1-(Z)phenyl-2-phenylethane-1,2-dione. The compound ofFormula (5) is a 1-((Z)phenyl)-2-hydrocarboxy-2-phenylethanone. Thecompound of Formula (6) is a2-((Z)phenyl)-2-hydrocarboxy-1-phenylethanone. The compound of Formula(7) is a 4-((Z)phenyl)-benzophenone. The compound of Formula (8) is a4-(Z)-4′-phenylbenzophenone. The compound of Formula (9) is a4-[((Z))phenoxy]-benzophenone. The compound of Formula (10) is a4-(Z)-4′-phenoxy-benzophenone. In this paragraph, (Z) represents thefunctional group.

In some other embodiments, the R and R′ groups attached to the ketonegroup form a ring structure. In such embodiments, the aromatic rings caninclude both aryl rings or heteroaryl rings. Examples of suchphotoactive moieties include those having the structure of one ofFormulas (13)-(14):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen.

The compound of Formula (13) is a(Z)dibenzo[1,3-e:1′,2′-f][7]annulen-11-one. The compound of Formula (14)is a (Z)thioxanthen-9-one. In this paragraph, (Z) represents thefunctional group.

The photoactive moiety is reacted with one or more linker moieties. Atleast one of the linker moieties comprises a plurality of linking groupsthat can react with the single functional group of the photoactivemoiety. The linking groups can be joined to an aliphatic group or anaromatic group which serves as a “backbone” for the linker moiety. Inparticular embodiments, the linker moiety can have two, three, four, oreven more linking groups.

Some examples of linker moieties which have two linking groups and canreact with the photoactive moieties include those having the structureof one of Formulas (30)-(33):

wherein Z is hydroxyl, amino, or —COY, where Y is hydroxyl, halogen,alkoxy, or aryloxy; and where n is 1 to 20. It should be noted thatFormula (32) encompasses isophthalic acid and terephthalic acid. Thenotation of Formula (33) indicates that the aliphatic backbone may haveany conformation and that the Z groups may be attached to any carbonatom in the aliphatic backbone.

Some examples of linker moieties which have three linking groups and canreact with the photoactive moieties include those having the structureof one of Formulas (34)-(36):

wherein Z is hydroxyl, amino, or —COY, where Y is hydroxyl, halogen,alkoxy, or aryloxy. The notation of Formula (35) indicates that thealiphatic backbone may have any conformation and that the Z groups maybe attached to any carbon atom in the aliphatic backbone.

Some examples of linker moieties which have four linking groups and canreact with the photoactive moieties include those having the structureof one of Formulas (37)-(40):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen; and where n is 1 to 20. The notation of Formula(39) indicates that the aliphatic backbone may have any conformation andthat the Z groups may be attached to any carbon atom in the aliphaticbackbone.

In some embodiments, linking groups can be provided by short oligomers,including oligomers containing glycidyl methacrylate monomers withstyrene or methacrylate monomers, or epoxidized novolac resins. Theseoligomers can permit the desired the number of functional groups to beprovided. Such oligomers are generalized by the structure of Formula(41):

where E is hydrogen or an endcapping agent, p is the number ofmethacrylate monomers, q is the number of methacrylate monomers, r isthe number of styrene monomers, and t is the number of epoxidizednovolac (phenol-formaldehyde) monomers. Generally, p+q+r+t≤20. When theoligomer contains glycidyl methacrylate monomers with styrene ormethacrylate monomers, generally t=0 and q≥1. Similarly, for novolacresins, p=q=r=0. The epoxy groups can be reacted with the phenolic groupof the photoactive moiety.

As discussed above, the photoactive moiety has one functional group andthe linker moiety has two or more linking groups. In embodiments thatuse only the photoactive moiety and the linker moiety in the reactionmixture, the resulting photoactive additive (PAA) will be a compound,each molecule having the same molecular weight. Again, the molar ratioof the photoactive moiety to the linker moiety can be from 1:2 to 20:1,though in these embodiments the molar ratio is usually 1:1 or greater.The two diagrams of FIG. 1 are illustrative of such photoactiveadditives. In the first diagram, two moles of 4-hydroxybenzophenone arereacted with one mole of phosgene to obtain the photoactive additive. Inthe second diagram, two moles of 4-hydroxybenzophenone are reacted withone mole of a diphthalic acid to obtain the photoactive additive. Theproduct of the first diagram contains carbonate linkages, while theproduct of the second diagram contains ester linkages.

In particularly desired embodiments, the photoactive additive can beformed from a reaction mixture containing the photoactive moiety, thefirst linker moiety, and one or more chain extenders. The chain extenderis a molecule that contains only two functional groups and is notphotoactive when exposed to light. The chain extender can be used toprovide a desired level of miscibility when the additive is mixed withthe polymeric resin. In particular embodiments, the photoactive additiveis a cross-linkable polycarbonate that includes a chain extender.

A first exemplary chain extender is a bisphenol of Formula (B):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen; R^(a) and R^(b) each represent a halogen atom or amonovalent hydrocarbon group and may be the same or different; p and qare each independently integers of 0 to 4; and A represents one of thegroups of formula (B-1):

wherein R^(c) and R^(d) each independently represent a hydrogen atom ora monovalent linear or cyclic hydrocarbon group and R^(e) is a divalenthydrocarbon group. For example, A can be a substituted or unsubstitutedC₃-C₁₈ cycloalkylidene.

Specific examples of the types of bisphenol compounds that may berepresented by Formula (B) include 1,1-bis(4-hydroxyphenyl) methane,1,1-bis(4-hydroxyphenyl) ethane, 2,2-bis(4-hydroxyphenyl) propane(hereinafter “bisphenol-A” or “BPA”), 2,2-bis(4-hydroxyphenyl) butane,2,2-bis(4-hydroxyphenyl) octane, 1,1-bis(4-hydroxyphenyl) propane,1,1-bis(4-hydroxyphenyl) n-butane, 2,2-bis(4-hydroxy-1-methylphenyl)propane, and 1,1-bis(4-hydroxy-t-butylphenyl) propane.

A second exemplary chain extender is a bisphenol of Formula (C):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen; each R^(k) is independently a C₁₋₁₀ hydrocarbongroup, and n is 0 to 4. The halogen is usually bromine. Examples ofcompounds that may be represented by Formula (C) include resorcinol,substituted resorcinol compounds such as 5-methyl resorcinol, 5-phenylresorcinol, or 5-cumyl resorcinol; catechol; hydroquinone; andsubstituted hydroquinones such as 2-methyl hydroquinone, 2-t-butylhydroquinone, 2-phenyl hydroquinone, 2-cumyl hydroquinone, or2,3,5,6-tetramethyl hydroquinone.

A third exemplary chain extender is a bisphenolpolydiorganosiloxane ofFormula (D-1) or (D-2):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen; each Ar is independently aryl; each R isindependently alkyl, alkoxy, alkenyl, alkenyloxy, aryl, aryloxy,arylalkyl, or alkylaryl; each R₆ is independently a divalent C₁-C₃₀organic group such as a C₁-C₃₀ alkyl, C₁-C₃₀ aryl, or C₁-C₃₀ alkylaryl;and D and E are an average value of 2 to about 1000, specifically about2 to about 500, or from about 10 to about 200, more specifically about10 to about 75.

Specific examples of Formulas (D-1) or (D-2) are illustrated below asFormulas (D-a) through (D-d):

where E is an average value from 10 to 200.

A fourth exemplary chain extender is an aliphatic compound of Formula(E):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen; each X is independently hydrogen, halogen, oralkyl; and j is an integer from 1 to 20. Examples of an aliphaticcompound include ethylene glycol, propanediol, 2,2-dimethyl-propanediol,1,6-hexanediol, and 1,12-dodecanediol.

A fifth exemplary chain extender is a dihydroxy compound of Formula (F),which may be useful for high heat applications:

wherein R¹³ and R¹⁵ are each independently a halogen or a C₁-C₆ alkylgroup, R¹⁴ is a C₁-C₆ alkyl, phenyl, or phenyl substituted with up tofive halogens or C₁-C₆ alkyl groups, and c is 0 to 4. In a specificembodiment, R¹⁴ is a C₁-C₆ alkyl or phenyl group. In still anotherembodiment, R¹⁴ is a methyl or phenyl group. In another specificembodiment, each c is 0. Compounds of Formula (F) include3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP);4,4′-(1-phenylethane-1,1-diyl)diphenol or1,1-bis(4-hydroxyphenyl)-1-phenyl-ethane (bisphenol-AP); and1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane) (bisphenol TMC).

Other chain extenders that might impart high Tgs to the polycarbonate asa copolycarbonate are dihydroxy compounds having adamantane units, asdescribed in U.S. Pat. No. 7,112,644 and U.S. Pat. No. 3,516,968, whichare fully incorporated herein by reference. A compound having adamantaneunits may have repetitive units of the following formula (G) for highheat applications:

wherein R₁ represents a halogen atom, an alkyl group having 1 to 6carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aryl grouphaving 6 to 12 carbon atoms, an aryl-substituted alkenyl group having 7to 13 carbon atoms, or a fluoroalkyl group having 1 to 6 carbon atoms;R₂ represents a halogen atom, an alkyl group having 1 to 12 carbonatoms, an alkoxy group having 1 to 12 carbon atoms, an aryl group having6 to 12 carbon atoms, an aryl-substituted alkenyl group having 7 to 13carbon atoms, or a fluoroalkyl group having 1 to 12 carbon atoms; mrepresents an integer of 0 to 4; and n represents an integer of 0 to 14.

Other dihydroxy compounds that might impart high Tgs to thepolycarbonate as a copolycarbonate are dihydroxy compounds havingfluorene-units, as described in U.S. Pat. No. 7,244,804. One suchfluorene-unit containing dihydroxy compound is represented by thefollowing formula (H) for high heat applications:

wherein R₁ to R₄ are each independently a hydrogen atom, a hydrocarbongroup with 1 to 9 carbon atoms which may contain an aromatic group, or ahalogen atom.

Another chain extender that could be used is an isosorbide. A monomerunit derived from isosorbide may be an isorbide-bisphenol unit ofFormula (J):

wherein R₁ is an isosorbide unit and R₂-R₉ are each independently ahydrogen, a halogen, a C₁-C₆ alkyl, a methoxy, an ethoxy, or an alkylester.

The R₁ isosorbide unit may be represented by Formula (J-a):

The isosorbide unit may be derived from an isosorbide, a mixture ofisosorbide, a mixture of isomers of isosorbide, and/or from individualisomers of isosorbide. The stereochemistry for the isosorbide-basedcarbonate units of Formula (J) is not particularly limited. These diolsmay be prepared by the dehydration of the corresponding hexitols.Hexitols are produced commercially from the corresponding sugars(aldohexose). Aliphatic diols of formula (16) include1,4:3,6-dianhydro-D glucitol, of formula (17); 1,4:3,6-dianhydro-Dmannitol, of formula (18); and 1,4:3,6-dianhydro-L iditol, of formula(19), and any combination thereof. Isosorbides are availablecommercially from various chemical suppliers including Cargill,Roquette, and Shanxi. The isosorbide-bisphenol may have a pKa of between8 and 11.

The cross-linkable polycarbonate of the present disclosure may be apolyester-polycarbonate copolymer. The molar ratio of ester units tocarbonate units in the polyester-polycarbonate may vary broadly, forexample 1:99 to 99:1, specifically 10:90 to 90:10, more specifically25:75 to 75:25, optionally expanded depending on the desired propertiesof the final composition. The polyester units may be derived from adicarboxylic acid, and may be, for example, a C₂-C₁₀ alkylene group, aC₆-C₂₀ alicyclic group, a C₆-C₂₀ alkyl aromatic group, a C₆-C₂₀ aromaticgroup, or a C₆-C₃₆ divalent organic group derived from a dihydroxycompound or chemical equivalent thereof.

The polyester units can be derived from aliphatic dicarboxylic acidshaving from 6 to about 36 carbon atoms, optionally from 6 to 20 carbonatoms. The C₆-C₂₀ linear aliphatic alpha-omega (α-ω) dicarboxylic acidsmay be adipic acid, sebacic acid, 3,3-dimethyl adipic acid,3,3,6-trimethyl sebacic acid, 3,3,5,5-tetramethyl sebacic acid, azelaicacid, dodecanedioic acid, dimer acids, cyclohexane dicarboxylic acids,dimethyl cyclohexane dicarboxylic acid, norbornane dicarboxylic acids,adamantane dicarboxylic acids, cyclohexene dicarboxylic acids, or C₁₄,C₁₈ and C₂₀ diacids.

Saturated aliphatic alpha-omega dicarboxylic acids may be adipic acid,sebacic or dodecanedioic acid. Sebacic acid has a molecular mass of202.25 Daltons, a density of 1.209 g/cm³ (25° C.), and a melting pointof 294.4° C. at 100 mmHg. Sebacic acid is extracted from castor bean oilfound in naturally occurring castor beans.

Other examples of aromatic dicarboxylic acids that may be used toprepare the polyester units include isophthalic or terephthalic acid,1,2-di(p-carboxyphenyl)ethane, 4,4′-dicarboxydiphenyl ether,4,4′-bisbenzoic acid, and combinations comprising at least one of theforegoing acids. Acids containing fused rings can also be present, suchas in 1,4-, 1,5-, or 2,6-naphthalenedicarboxylic acids. Specificdicarboxylic acids may be terephthalic acid, isophthalic acid,naphthalene dicarboxylic acid, cyclohexane dicarboxylic acid, orcombinations thereof. A specific dicarboxylic acid comprises acombination of isophthalic acid and terephthalic acid wherein the weightratio of isophthalic acid to terephthalic acid is about 91:9 to about2:98.

Mixtures of the diacids can also be employed. It should be noted thatalthough referred to as diacids, any ester precursor could be employedsuch as acid halides, specifically acid chlorides, and diaromatic estersof the diacid such as diphenyl, for example the diphenyl ester ofsebacic acid. With reference to the diacid carbon atom number earliermentioned, this does not include any carbon atoms which may be includedin the ester precursor portion, for example diphenyl. It may bedesirable that at least four, five or six carbon bonds separate the acidgroups. This may reduce the formation of undesirable and unwanted cyclicspecies.

The polyester unit of a polyester-polycarbonate may be derived from thereaction of a combination of isophthalic and terephthalic diacids (orderivatives thereof) with resorcinol. In another embodiment, thepolyester unit of a polyester-polycarbonate may be derived from thereaction of a combination of isophthalic acid and terephthalic acid withbisphenol-A. In an embodiment, the polycarbonate units may be derivedfrom bisphenol-A. In another specific embodiment, the polycarbonateunits may be derived from resorcinol and bisphenol-A in a molar ratio ofresorcinol carbonate units to bisphenol-A carbonate units of 1:99 to99:1.

The polyester-polycarbonate may have a biocontent according toASTM-D-6866 of at least 2 weight %, at least 3 weight %, at least 4weight %, at least 5 weight %, at least 6 weight %, at least 7 weight %,at least 8 weight %, at least 9 weight %, at least 10 weight %, at least11 weight %, at least 12 weight %, at least 13 weight %, at least 14weight %, at least 15 weight %, at least 16 weight %, at least 17 weight%, at least 18 weight %, at least 19 weight %, at least 20 weight %, atleast 25 weight %, at least 30 weight %, at least 35 weight %, at least40 weight %, at least 45 weight %, at least 50 weight %, at least 55weight %, at least 60 weight %, or at least 65 weight % of thecomposition derived therefrom. The polymer, or any composition derivedtherefrom, may have at least 5.0 weight percent of sebacic acid content.

In such embodiments, a second end-capping agent can also be used toterminate any chains (in addition to the photoactive moiety with onlyone functional group). The second end-capping agent (i.e. chain stopper)is a monohydroxy compound, a mono-acid compound, or a mono-estercompound. Exemplary endcapping agents include p-cumylphenol (PCP),resorcinol monobenzoate, p-tert-butylphenol, and p-methoxyphenol. Theterm “end-capping agent” is used herein to denote a compound that is notphotoactive when exposed to light. For example, the end-capping agentdoes not contain a ketone group.

The resulting photoactive additive (PAA) may be an oligomer or a polymerwith a weight average molecular weight and a polydispersity index. Theproduct resulting from the reaction in FIG. 2 is illustrative of suchphotoactive additives. Here, bisphenol-A is reacted with phosgene,4-hydroxybenzophenone, and p-cumylphenol (endcap) to obtain thephotoactive additive. Some chains will have two 4-hydroxybenzophenoneendcaps, some will have only one 4-hydroxybenzophenone endcap, and somewill have none, distributed in a statistical fashion.

Another example of a photoactive additive formed from a firstphotoactive moiety, a first linker moiety, and a chain extender is seenin FIG. 3. 4-hydroxybenzophenone (first photoactive moiety) is reactedwith phosgene (first linker moiety) and bisphenol-A (chain extender) toobtain the photoactive additive. The resulting photoactive additive(PAA) may be an oligomer with a weight average molecular weight and apolydispersity index.

As previously explained, a first photoactive moiety is reacted with afirst linker moiety to obtain the photoactive additive. In someembodiments, a secondary linker moiety is included in the reactionmixture. The secondary linker moiety has at least three functionalgroups, each of which can react with the linking groups of the firstlinker moiety, and acts as a branching agent. Generally, the functionalgroups of the secondary linker moiety are the same as those on thephotoactive moiety. When the photoactive moiety has one functionalgroup, the resulting photoactive additive (PAA) will be a compound, eachmolecule having the same molecular weight.

Some examples of secondary linker moieties which have three functionalgroups and can react with the first linker moiety include those havingthe structure of one of Formulas (43)-(46):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen.

Some examples of secondary linker moieties which have four functionalgroups and can react with the first linker moiety include those havingthe structure of one of Formulas (47)-(48):

wherein Z is hydroxyl, amino, or —COY, wherein Y is hydroxyl, alkoxy,aryloxy, or halogen.

In some embodiments, the secondary linker moiety can be an oligomer,made from an epoxidized novolac monomer. These oligomers can permit thedesired number of functional groups to be provided. Such oligomers aregeneralized by the structure of Formula (49):

wherein E is hydrogen or an endcapping agent; and t is an integer from 1to 20.

An example of a photoactive additive formed from a first photoactivemoiety, a first linker moiety, and a secondary linker moiety is seen inFIG. 4. Here, two moles of 4-hydroxybenzophenone are reacted with threemoles of phosgene (first linker moiety) and one mole oftris(hydroxyphenyl)ethane (THPE, secondary linker moiety) to obtain thephotoactive additive. Note that the secondary linker moiety reacts withthe first linker moiety, not with the photoactive moiety.

Some photoactive additives of the present disclosure can be formed fromthe reaction of a first photoactive moiety, a chain extender, a firstlinker moiety, and a secondary linker moiety. Such a reaction is seen inFIG. 5. Here, 4-hydroxybenzophenone, bisphenol-A, phosgene, and THPE arereacted to obtain the photoactive additive. The resulting photoactiveadditive (PAA) may be an oligomer or a polymer with a weight averagemolecular weight and a polydispersity index.

The photoactive additives of the present disclosure can be a compound,an oligomer, or a polymer. The oligomer has a weight average molecularweight (Mw) of less than 15,000, including 10,000 or less. The polymericphotoactive additives of the present disclosure have a Mw of 15,000 orhigher. In particular embodiments, the Mw is between 17,000 and 80,000Daltons, or between 17,000 and 35,000 Daltons. The Mw may be varied asdesired. Polymers/oligomers with relatively higher Mw's generally retaintheir mechanical properties better, while polymers/oligomers withrelatively lower Mw's generally have better flow properties. In someparticular embodiments, the Mw of the photoactive additives is about5,000 or less. During melt processing, such oligomers are more likely torise to the surface of the article. Long chain aliphatic diols (C₆ orhigher) can also be used for this purpose. This may increase theconcentration of the additive at the surface, and thus increase thecrosslinking density at the surface upon exposure to UV light as well.

The photoactive additives (PAA) can be prepared by suitable methods. Itmay be advantageous to pre-react any phenolic groups with phosgene toform chloroformates. The chloroformates can then be condensed with theother reactants with the aid of a condensation catalyst, such astriethylamine. This can result in a substantially pure product.Alternatively, a mixture of additives can be obtained by mixing all ofthe reactants together upfront and then reacting.

The crosslinking mechanism of the additives is believed to be due tohydrogen abstraction by the ketone group from an alkyl group that actsas a hydrogen donor and subsequent coupling of the resulting radicals.This mechanism is illustrated in FIG. 6 with reference to a benzophenone(the photoactive moiety) and a bisphenol-A (BPA) monomer. Upon exposureto UV, the oxygen atom of the benzophenone abstracts a hydrogen atomfrom a methyl group on the BPA monomer and becomes a hydroxyl group. Themethylene group then forms a covalent bond with the carbon of the ketonegroup. Put another way, the ketone group of the benzophenone could beconsidered to be a photoactive group. It should be noted that thepresence of hydrogen is critical for the reaction to occur.

In particular embodiments, the photoactive additives (PAAs) disclosedherein are cross-linkable polycarbonates comprising endcaps derived froma monofunctional benzophenone (i.e. of Formula (1)). In more specificembodiments, the monofunctional benzophenone is amonohydroxybenzophenone. These polycarbonates, prior to cross-linking,can be provided as thermally stable high melt-flow polymers, and canthus be used to fabricate a variety of thin-walled articles (e.g., 3 mmor less). These articles may subsequently be treated (e.g., withUV-radiation) to affect cross-linking, thereby providing thin-walledmaterials that meet desired performance requirements (e.g., 5VAperformance, chemical resistance, transparency). The cross-linkedmaterials, in addition to flame resistance and chemical resistance, mayretain or exhibit superior mechanical properties (e.g., impactresistance, ductility) as compared to the composition prior tocross-linking.

The use of monohydroxybenzophenone derived endcaps provides severaladvantages over polycarbonates incorporating repeating units derivedfrom dihydroxybenzophenone monomers. Specifically, themonohydroxybenzophenone endcap is more economical, as less monomer istypically used. In addition, incorporation of themonohydroxybenzophenone into the polycarbonate can be particularlycontrolled, as the monohydroxybenzophenone will only react as a chainstopper. Accordingly, use of monohydroxybenzophenone eliminates the needfor careful monitoring of polymerization kinetics or how the monomer isincorporated, as compared with a corresponding dihydroxybenzophenonemonomer.

The monohydroxybenzophenone endcaps of the cross-linkable polycarbonatesprovide a reactive functional group for cross-linking thepolycarbonates. For example, treatment of a cross-linkable polycarbonateof the invention with a suitable dose of ultra-violet radiation, asfurther described herein, may initiate cross-linking reaction betweenthe monohydroxybenzophenone carbonyl carbon and a carbon atom of anotherfunctional group (e.g., a methylene carbon atom, such as in bisphenol-A)in the same polymer or another polymer in the composition.

Suitable monohydroxybenzophenone chain-stoppers include, but are notlimited to, 2-hydroxybenzophenone, 3-hydroxybenzophenone,4-hydroxybenzophenone, 4-hydroxybenzoylbenzophenone,2-hydroxy-4-methoxybenzophenone,2-hydroxy-4-methoxy-2′-carboxybenzophenone,2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-stearoxybenzophenone,4-dodecyloxy-2-hydroxybenzophenone,2-hydroxy-4-methoxy-5-sulfobenzophenone trihydrate, and2-hydroxy-4-methoxybenzophenone-5-sulfonic acid. In one preferredembodiment, the monohydroxybenzophenone chain stopper is a2-hydroxybenzophenone, 3-hydroxybenzophenone, or 4-hydroxybenzophenone,each of which may be further substituted with one or more additionalsubstituents, provided the monohydroxybenzophenone still functions as achain-stopper. In another preferred embodiment, themonohydroxybenzophenone is 4-hydroxybenzophenone.

The cross-linkable polycarbonates (also referred to as “non-cross-linkedpolycarbonates”) may comprise about 0.5 mol % to about 5 mol % endcapgroups derived from a monohydroxybenzophenone, about 1 mol % to about 3mol % endcap groups derived from a monohydroxybenzophenone, about 1.7mol % to about 2.5 mol % endcap groups derived from amonohydroxybenzophenone, about 2 mol % to about 2.5 mol % endcap groupsderived from a monohydroxybenzophenone, or about 2.5 mol % to about 3.0mol % endcap groups derived from a monohydroxybenzophenone. Thecross-linkable polycarbonates may have a monohydroxybenzophenone derivedendcap content of: 0.5 mol %, 0.6 mol %, 0.7 mol %, 0.8 mol %, 0.9 mol%, 1.0 mol %, 1.1 mol %, 1.2 mol %, 1.3 mol %, 1.4 mol %, 1.5 mol %, 1.6mol %, 1.7 mol %, 1.8 mol %, 1.9 mol %, 2.0 mol %, 2.1 mol %, 2.2 mol %,2.3 mol %, 2.4 mol %, 2.5 mol %, 2.6 mol %, 2.7 mol %, 2.8 mol %, 2.9mol %, 3.0 mol %, 3.1 mol %, 3.2 mol %, 3.3 mol %, 3.4 mol %, 3.5 mol %,3.6 mol %, 3.7 mol %, 3.8 mol %, 3.9 mol %, 4.0 mol %, 4.1 mol %, 4.2mol %, 4.3 mol %, 4.4 mol %, 4.5 mol %, 4.6 mol %, 4.7 mol %, 4.8 mol %,4.9 mol %, or 5.0 mol %.

As described above, other end-capping agents can be incorporated intothe cross-linkable polycarbonates. Exemplary chain-stoppers includecertain monophenolic compounds (i.e., phenyl compounds having a singlefree hydroxy group), monocarboxylic acid chlorides, monocarboxylicacids, and/or monochloroformates. Phenolic chain-stoppers areexemplified by phenol and C₁-C₂₂ alkyl-substituted phenols such asp-cumyl-phenol, resorcinol monobenzoate, and p-tertiary-butylphenol,cresol, and monoethers of diphenols, such as p-methoxyphenol. Exemplarychain-stoppers also include cyanophenols, such as for example,4-cyanophenol, 3-cyanophenol, 2-cyanophenol, and polycyanophenols.Alkyl-substituted phenols with branched chain alkyl substituents having8 to 9 carbon atoms can be specifically be used.

Endgroups can be derived from the carbonyl source (i.e., the diarylcarbonate or carbonate precursor, or first linker moiety), fromselection of monomer ratios, incomplete polymerization, chain scission,and the like, as well as any added endcapping groups, and can includederivatizable functional groups such as hydroxy groups, carboxylic acidgroups, or the like. In an embodiment, the endgroup of a polycarbonatecan comprise a structural unit derived from a diaryl carbonate, wherethe structural unit can be an endgroup. In a further embodiment, theendgroup is derived from an activated carbonate. Such endgroups canderive from the transesterification reaction of the alkyl ester of anappropriately substituted activated carbonate, with a hydroxy group atthe end of a polycarbonate polymer chain, under conditions in which thehydroxy group reacts with the ester carbonyl from the activatedcarbonate, instead of with the carbonate carbonyl of the activatedcarbonate. In this way, structural units derived from ester containingcompounds or substructures derived from the activated carbonate andpresent in the melt polymerization reaction can form ester endgroups. Inan embodiment, the ester endgroup derived from a salicylic ester can bea residue of bis(methyl salicyl) carbonate (BMSC) or other substitutedor unsubstituted bis(alkyl salicyl) carbonate such as bis(ethyl salicyl)carbonate, bis(propyl salicyl) carbonate, bis(phenyl salicyl) carbonate,bis(benzyl salicyl) carbonate, or the like. In a specific embodiment,where BMSC is used as the activated carbonyl source, the endgroup isderived from and is a residue of BMSC.

The cross-linkable polycarbonates of the present disclosure includehomopolycarbonates, copolymers comprising different moieties in thecarbonate (referred as “copolycarbonates”), copolymers comprisingcarbonate units and other types of polymer units such as polyesterunits, polysiloxane units, and combinations comprising at least onehomopolycarbonate and copolycarbonate. For reference, the term“dipolymer” refers to copolymers derived specifically from two differentmonomers, and the term “terpolymer” refers to copolymers derivedspecifically from three different monomers

The cross-linkable polycarbonate may thus comprise identical ordifferent repeating units derived from one or more monomers (e.g. asecond, third, fourth, fifth, sixth, etc., other monomer compound). Themonomers of the cross-linkable polycarbonate may be randomlyincorporated into the polycarbonate. For example, a cross-linkablepolycarbonate copolymer of the present disclosure may be arranged in analternating sequence following a statistical distribution, which isindependent of the mole ratio of the structural units present in thepolymer chain. A random cross-linkable polycarbonate copolymer may havea structure, which can be indicated by the presence of several blocksequences (I—I) and (O—O) and alternate sequences (I—O) or (O—I), thatfollow a statistical distribution. In a random x:(1-x) copolymer,wherein x is the mole percent of a first monomer(s) and 1-x is the molepercent of the monomers, one can calculate the distribution of eachmonomer using peak area values determined by ¹³C NMR, for example.

A cross-linkable polycarbonate copolymer of the present disclosure mayhave alternating I and O units (—I—O—I—O—I—O—I—O—), or I and O unitsarranged in a repeating sequence (e.g. a periodic copolymer having theformula: (I—O—I—O—O—I—I—I—I—O—O—O)n). The cross-linkable polycarbonatecopolymer may be a statistical copolymer in which the sequence ofmonomer residues follows a statistical rule. For example, if theprobability of finding a given type monomer residue at a particularpoint in the chain is equal to the mole fraction of that monomer residuein the chain, then the polymer may be referred to as a truly randomcopolymer. The cross-linkable polycarbonate copolymer may be a blockcopolymer that comprises two or more homopolymer subunits linked bycovalent bonds (—I—I—I—I—I—O—O—O—O—O—). The union of the homopolymersubunits may require an intermediate non-repeating subunit, known as ajunction block. Block copolymers with two or three distinct blocks arecalled diblock copolymers and triblock copolymers, respectively.

The cross-linkable polycarbonates of the present disclosure may includeany suitable mole % of selected monomer units, with the proviso that thepolycarbonates comprise a mol % (e.g., about 0.5 mol % to about 5 mol %)of endcap groups derived from a monohydroxybenzophenone. The polymersmay comprise about 1% to about 99.5%, about 5% to about 95%, about 10%to about 90%, about 15% to about 85%, about 20% to about 80%, about 25%to about 75%, about 30% to about 70%, about 35% to about 65%, about 40%to about 60%, or about 45% to about 55% mole % of a selected monomerunit.

The cross-linkable polycarbonates of the present disclosure may have aglass transition temperature (Tg) of greater than 120° C., 125° C., 130°C., 135° C., 140° C., 145° C., 150° C., 155° C., 160° C., 165° C., 170°C., 175° C., 180° C., 185° C., 190° C., 200° C., 210° C., 220° C., 230°C., 240° C., 250° C., 260° C., 270° C., 280° C., 290° C., or 300° C., asmeasured using a differential scanning calorimetry method. In certainembodiments, the polycarbonates have glass transition temperaturesranging from about 120° C. to about 230° C., about 140° C. to about 160°C., about 145° C. to about 155° C., about 148° C. to about 152° C., orabout 149° C. to about 151° C. In certain embodiments, thepolycarbonates have glass transition temperatures of 149.0° C., 149.1°C., 149.2° C., 149.3° C., 149.4° C., 149.5° C., 149.6° C., 149.7° C.,149.8° C., 149.9° C., 150.0° C., 150.1° C., 150.2° C., 150.3° C., 150.4°C., 150.5° C., 150.6° C., 150.7° C., 150.8° C., 150.9° C., 151.0° C.,151.1° C., 151.2° C., 151.3° C., 151.4° C., 151.5° C., 151.6° C., 151.7°C., 151.8° C., 151.9° C., 152.0° C., 152.1° C., 152.2° C., 152.3° C.,152.4° C., 152.5° C., 152.6° C., 152.7° C., 152.8° C., 152.9° C., or153.0° C.

The cross-linkable polycarbonates of the present disclosure may have aweight average molecular weight (Mw) of 15,000 to about 80,000 Daltons[±1,000 Daltons], or of 15,000 to about 35,000 Daltons [±1,000 Daltons],or of about 20,000 to about 30,000 Daltons [±1,000 Daltons]. In certainembodiments, the cross-linkable polycarbonates have weight averagemolecular weights of about 16,000 Daltons [±1,000 Daltons], about 17,000Daltons [±1,000 Daltons], about 18,000 Daltons [±1,000 Daltons], about19,000 Daltons [±1,000 Daltons], about 20,000 Daltons [±1,000 Daltons],about 21,000 Daltons [±1,000 Daltons], about 22,000 Daltons [±1,000Daltons], about 23,000 Daltons [±1,000 Daltons], about 24,000 Daltons[±1,000 Daltons], about 25,000 Daltons [±1,000 Daltons], about 26,000Daltons [±1,000 Daltons], about 27,000 Daltons [±1,000 Daltons], about28,000 Daltons [±1,000 Daltons], about 29,000 Daltons [±1,000 Daltons],about 30,000 Daltons [±1,000 Daltons], about 31,000 Daltons [±1,000Daltons], about 32,000 Daltons [±1,000 Daltons], about 33,000 Daltons[±1,000 Daltons], about 34,000 Daltons [±1,000 Daltons], or about 35,000Daltons [±1,000 Daltons]. In additional embodiments, the cross-linkablepolycarbonates have a Mw of 17,000 to about 80,000 Daltons. Molecularweight determinations may be performed using gel permeationchromatography (GPC), using a cross-linked styrene-divinylbenzene columnand calibrated to polycarbonate references using a UV detector set at264 nm. Samples may be prepared at a concentration of about 1 mg/ml, andeluted at a flow rate of about 1.0 ml/min.

The cross-linkable polycarbonates of the present disclosure may have apolydispersity index (PDI) of about 1.0 to about 10.0, about 2.0 toabout 7.0, or about 3.0 to about 6.0, or about 3.0 to about 7.3, orabout 2.4 to about 5.2. In certain embodiments, the polycarbonates havePDIs of about 2.50, about 3.00, about 3.50, about 4.00, about 4.50,about 5.00, about 5.50, about 6.00, about 6.50, about 7.00, or about7.50.

It is noted that the molecular weight (both weight-average andnumber-average) of the photoactive additive/cross-linkable polycarbonatecan be measured using two different kinds of detectors. Morespecifically, the molecular weight can be measured using an ultraviolet(UV) detector or using a refractive index (RI) detector, using GPC andcalibrated to polycarbonate standards for both detectors. In thisregard, the UV detector overweights the presence of low-molecular-weightchains due to the higher extinction coefficient of themonohydroxybenzophenone in the UV detector. This does not occur in theRI detector, and so the PDI as measured by the RI detector is alwayslower than the PDI as measured by the UV detector.

In embodiments, the ratio of the polydispersity index (PDI) measuredusing a UV detector to the PDI measured using an RI detector is 1.8 orless, when using a GPC method and polycarbonate molecular weightstandards. The ratio may also be 1.5 or less, or 1.2 or less. The PDIratio has a minimum value of 1.0. As described further herein, theprocess by which the cross-linkable polycarbonate is made can affect thePDI ratio between the UV detector and the RI detector.

The cross-linkable polycarbonates of the present disclosure may have amelt volume flow rate (often abbreviated MVR), which measures the rateof extrusion of a composition through an orifice at a prescribedtemperature and load. In certain embodiments, the polycarbonates mayhave an MVR of 2 to 4 cm³/10 min, 2 to 12 cm³/10 min, 2 to 70 cm³/10min, 2 to 50 cm³/10 min, 2 to 40 cm³/10 min, 2 to 30 cm³/10 min, 2 to 25cm³/10 min, 2 to 20 cm³/10 min, 5 to 70 cm³/10 min, 5 to 50 cm³/10 min,5 to 40 cm³/10 min, 5 to 30 cm³/10 min, 5 to 25 cm³/10 min, 5 to 20cm³/10 min, 8 to 10 cm³/10 min, 8 to 12 cm³/10 min, 10 to 170 cm³/10min, 10 to 50 cm³/10 min, 10 to 40 cm³/10 min, 10 to 30 cm³/10 min, 10to 25 cm³/10 min, or 10 to 20 cm³/10 min, using the ASTM D1238 method,1.2 kg load, 300° C. temperature, 360 second dwell. In certainembodiments, the polycarbonates may have an MVR measured using the ASTMD1238 method, 1.2 kg load, 300° C. temperature, 360 second dwell, of:2.0 cm³/10 min, 2.1 cm³/10 min, 2.2 cm³/10 min, 2.3 cm³/10 min, 2.4cm³/10 min, 2.5 cm³/10 min, 2.6 cm³/10 min, 2.7 cm³/10 min, 2.8 cm³/10min, 2.9 cm³/10 min, 3.0 cm³/10 min, 3.1 cm³/10 min, 3.2 cm³/10 min, 3.3cm³/10 min, 3.4 cm³/10 min, 3.5 cm³/10 min, 3.6 cm³/10 min, 3.7 cm³/10min, 3.8 cm³/10 min, 3.9 cm³/10 min, 4.0 cm³/10 min, 4.1 cm³/10 min, 4.2cm³/10 min, 4.3 cm³/10 min, 4.4 cm³/10 min, 4.5 cm³/10 min, 4.6 cm³/10min, 4.7 cm³/10 min, 4.8 cm³/10 min, 4.9 cm³/10 min, 5.0 cm³/10 min, 5.1cm³/10 min, 5.2 cm³/10 min, 5.3 cm³/10 min, 5.4 cm³/10 min, 5.5 cm³/10min, 5.6 cm³/10 min, 5.7 cm³/10 min, 5.8 cm³/10 min, 5.9 cm³/10 min, 6.0cm³/10 min, 6.1 cm³/10 min, 6.2 cm³/10 min, 6.3 cm³/10 min, 6.4 cm³/10min, 6.5 cm³/10 min, 6.6 cm³/10 min, 6.7 cm³/10 min, 6.8 cm³/10 min, 6.9cm³/10 min, 7.0 cm³/10 min, 7.1 cm³/10 min, 7.2 cm³/10 min 7.3 cm³/10min, 7.4 cm³/10 min, 7.5 cm³/10 min, 7.6 cm³/10 min, 7.7 cm³/10 min, 7.8cm³/10 min, 7.9 cm³/10 min, 8.0 cm³/10 min, 8.1 cm³/10 min, 8.2 cm³/10min, 8.3 cm³/10 min, 8.4 cm³/10 min, 8.5 cm³/10 min, 8.6 cm³/10 min, 8.7cm³/10 min, 8.8 cm³/10 min, 8.9 cm³/10 min, 9.0 cm³/10 min, 9.1 cm³/10min, 9.2 cm³/10 min, 9.3 cm³/10 min, 9.4 cm³/10 min, 9.5 cm³/10 min, 9.6cm³/10 min, 9.7 cm³/10 min, 9.8 cm³/10 min, 9.9 cm³/10 min, 10.0 cm³/10min, 10.1 cm³/10 min, 10.2 cm³/10 min, 10.3 cm³/10 min, 10.4 cm³/10 min,10.5 cm³/10 min, 10.6 cm³/10 min, 10.7 cm³/10 min, 10.8 cm³/10 min, 10.9cm³/10 min, 11.0 cm³/10 min, 11.1 cm³/10 min, 11.2 cm³/10 min, 11.3cm³/10 min, 11.4 cm³/10 min, 11.5 cm³/10 min, 11.6 cm³/10 min, 11.7cm³/10 min, 11.8 cm³/10 min, 11.9 cm³/10 min, 12.0 cm³/10 min, 12.1cm³/10 min, 12.2 cm³/10 min, 12.3 cm³/10 min, 12.4 cm³/10 min, 12.5cm³/10 min, 12.6 cm³/10 min, 12.7 cm³/10 min, 12.8 cm³/10 min, 12.9cm³/10 min, 13.0 cm³/10 min, 13.1 cm³/10 min, 13.2 cm³/10 min, 13.3cm³/10 min, 13.4 cm³/10 min, 13.5 cm³/10 min, 13.6 cm³/10 min, 13.7cm³/10 min, 13.8 cm³/10 min, 13.9 cm³/10 min, 14.0 cm³/10 min, 14.1cm³/10 min, 14.2 cm³/10 min, 14.3 cm³/10 min, 14.4 cm³/10 min. 14.5cm³/10 min, 14.6 cm³/10 min, 14.7 cm³/10 min, 14.8 cm³/10 min, 14.9cm³/10 min, 15.0 cm³/10 min, 15.1 cm³/10 min, 15.2 cm³/10 min, 15.3cm³/10 min, 15.4 cm³/10 min, 15.5 cm³/10 min, 15.6 cm³/10 min, 15.7cm³/10 min, 15.8 cm³/10 min, 15.9 cm³/10 min, 16.0 cm³/10 min, 16.1cm³/10 min, 16.2 cm³/10 min, 16.3 cm³/10 min, 16.4 cm³/10 min, 16.5cm³/10 min, 16.6 cm³/10 min, 16.7 cm³/10 min, 16.8 cm³/10 min, 16.9cm³/10 min, 17.0 cm³/10 min, 17.1 cm³/10 min, 17.2 cm³/10 min, 17.3cm³/10 min, 17.4 cm³/10 min, 17.5 cm³/10 min, 17.6 cm³/10 min, 17.7cm³/10 min, 17.8 cm³/10 min, 17.9 cm³/10 min, 18.0 cm³/10 min, 18.1cm³/10 min, 18.2 cm³/10 min, 18.3 cm³/10 min, 18.4 cm³/10 min, 18.5cm³/10 min, 18.6 cm³/10 min 18.7 cm³/10 min, 18.8 cm³/10 min, 18.9cm³/10 min, 19.0 cm³/10 min, 19.1 cm³/10 min, 19.2 cm³/10 min, 19.3cm³/10 min, 19.4 cm³/10 min, 19.5 cm³/10 min, 19.6 cm³/10 min, 19.7cm³/10 min, 19.8 cm³/10 min, 19.9 cm³/10 min, 20.0 cm³/10 min, 20.1cm³/10 min, 20.2 cm³/10 min, 20.3 cm³/10 min, 20.4 cm³/10 min, 20.5cm³/10 min, 20.6 cm³/10 min, 20.7 cm³/10 min, 20.8 cm³/10 min, 20.9cm³/10 min, 21.0 cm³/10 min, 21.1 cm³/10 min, 21.2 cm³/10 min, 21.3cm³/10 min, 21.4 cm³/10 min, 21.5 cm³/10 min, 21.6 cm³/10 min, 21.7cm³/10 min, 21.8 cm³/10 min, 21.9 cm³/10 min, 22.0 cm³/10 min, 22.1cm³/10 min, 22.2 cm³/10 min, 22.3 cm³/10 min, 22.4 cm³/10 min, 22.5cm³/10 min, 22.6 cm³/10 min, 22.7 cm³/10 min, 22.8 cm³/10 min, 22.9cm³/10 min, 23.0 cm³/10 min, 23.1 cm³/10 min, 23.2 cm³/10 min, 23.3cm³/10 min, 23.4 cm³/10 min, 23.5 cm³/10 min, 23.6 cm³/10 min, 23.7cm³/10 min, 23.8 cm³/10 min, 23.9 cm³/10 min, 24.0 cm³/10 min, 24.1cm³/10 min, 24.2 cm³/10 min, 24.3 cm³/10 min, 24.4 cm³/10 min, 24.5cm³/10 min, 24.6 cm³/10 min, 24.7 cm³/10 min, 24.8 cm³/10 min, 24.9cm³/10 min, 25.0 cm³/10 min, 25.1 cm³/10 min, 25.2 cm³/10 min, 25.3cm³/10 min, 25.4 cm³/10 min, 25.5 cm³/10 min, 25.6 cm³/10 min, 25.7cm³/10 min, 25.8 cm³/10 min, 25.9 cm³/10 min, 26.0 cm³/10 min, 26.1cm³/10 min, 26.2 cm³/10 min, 26.3 cm³/10 min, 26.4 cm³/10 min, 26.5cm³/10 min, 26.6 cm³/10 min, 26.7 cm³/10 min, 26.8 cm³/10 min, 26.9cm³/10 min, 27.0 cm³/10 min, 27.1 cm³/10 min, 27.2 cm³/10 min, 27.3cm³/10 min, 27.4 cm³/10 min, 27.5 cm³/10 min, 27.6 cm³/10 min, 27.7cm³/10 min, 27.8 cm³/10 min, 27.9 cm³/10 min, 28.0 cm³/10 min, 28.1cm³/10 min, 28.2 cm³/10 min, 28.3 cm³/10 min, 28.4 cm³/10 min, 28.5cm³/10 min, 28.6 cm³/10 min, 28.7 cm³/10 min, 28.8 cm³/10 min, 28.9cm³/10 min, 29.0 cm³/10 min, 29.1 cm³/10 min, 29.2 cm³/10 min, 29.3cm³/10 min, 29.4 cm³/10 min, 29.5 cm³/10 min, 29.6 cm³/10 min, 29.7cm³/10 min, 29.8 cm³/10 min, 29.9 cm³/10 min, 30.0 cm³/10 min, 30.1cm³/10 min, 30.2 cm³/10 min, 30.3 cm³/10 min, 30.4 cm³/10 min, 30.5cm³/10 min, 30.6 cm³/10 min, 30.7 cm³/10 min, 30.8 cm³/10 min, 30.9cm³/10 min, 31.0 cm³/10 min, 31.1 cm³/10 min, 31.2 cm³/10 min, 31.3cm³/10 min, 31.4 cm³/10 min, 31.5 cm³/10 min, 31.6 cm³/10 min, 31.7cm³/10 min, 31.8 cm³/10 min, 31.9 cm³/10 min, 32.0 cm³/10 min, 32.1cm³/10 min, 32.2 cm³/10 min, 32.3 cm³/10 min, 32.4 cm³/10 min, 32.5cm³/10 min, 32.6 cm³/10 min, 32.7 cm³/10 min, 32.8 cm³/10 min, 32.9cm³/10 min, 33.0 cm³/10 min, 33.1 cm³/10 min, 33.2 cm³/10 min, 33.3cm³/10 min, 33.4 cm³/10 min, 33.5 cm³/10 min, 33.6 cm³/10 min, 33.7cm³/10 min, 33.8 cm³/10 min, 33.9 cm³/10 min, 34.0 cm³/10 min, 34.1cm³/10 min, 34.2 cm³/10 min, 34.3 cm³/10 min, 34.4 cm³/10 min, 34.5cm³/10 min, 34.6 cm³/10 min, 34.7 cm³/10 min, 34.8 cm³/10 min, 34.9cm³/10 min, or 35.0 cm³/10 min.

The cross-linkable polycarbonates of the present disclosure may have abiocontent of 2 weight % to 90 weight %; 5 weight % to 25 weight %; 10weight % to 30 weight %; 15 weight % to 35 weight %; 20 weight % to 40weight %; 25 weight % to 45 weight %; 30 weight % to 50 weight %; 35weight % to 55 weight %; 40 weight % to 60 weight %; 45 weight % to 65weight %; 55 weight % to 70% weight %; 60 weight % to 75 weight %; 50weight % to 80 weight %; or 50 weight % to 90 weight %. The biocontentmay be measured according to ASTM D6866.

The cross-linkable polycarbonates of the present disclosure may have amodulus of elasticity of greater than or equal to 2200 megapascals(MPa), greater than or equal to 2310 MPa, greater than or equal to 2320MPa, greater than or equal to 2330 MPa, greater than or equal to 2340MPa, greater than or equal to 2350 MPa, greater than or equal to 2360MPa, greater than or equal to 2370 MPa, greater than or equal to 2380MPa, greater than or equal to 2390 MPa, greater than or equal to 2400MPa, greater than or equal to 2420 MPa, greater than or equal to 2440MPa, greater than or equal to 2460 MPa, greater than or equal to 2480MPa, greater than or equal to 2500 MPa, or greater than or equal to 2520MPa as measured by ASTM D 790 at 1.3 mm/min, 50 mm span.

In an embodiment the cross-linkable polycarbonates of the presentdisclosure may have a flexural modulus of 2,200 to 2,500, preferably2,250 to 2,450, more preferably 2,300 to 2,400 MPa. The flexural modulusis also measured by ASTM D790.

In another embodiment the cross-linkable polycarbonates of the presentdisclosure may have a flexural modulus of 2,300 to 2,600, preferably2,400 to 2,600, more preferably 2,450 to 2,550 MPa.

The cross-linkable polycarbonates of the present disclosure may have atensile strength at break of greater than or equal to 60 megapascals(MPa), greater than or equal to 61 MPa, greater than or equal to 62 MPa,greater than or equal to 63 MPa, greater than or equal to 64 MPa,greater than or equal to 65 MPa, greater than or equal to 66 MPa,greater than or equal to 67 MPa, greater than or equal to 68 MPa,greater than or equal to 69 MPa, greater than or equal to 70 MPa,greater than or equal to 71 MPa, greater than or equal to 72 MPa,greater than or equal to 73 MPa, greater than or equal to 74 MPa,greater than or equal to 75 MPa as measured by ASTM D 638 Type I at 50mm/min.

The cross-linkable polycarbonates of the present disclosure may possessa ductility of greater than or equal to 60%, greater than or equal to65%, greater than or equal to 70%, greater than or equal to 75%, greaterthan or equal to 80%, greater than or equal to 85%, greater than orequal to 90%, greater than or equal to 95%, or 100% in a notched izodtest at −20° C., −15° C., −10° C., 0° C., 5° C., 10° C., 15° C., 20° C.,23° C., 25° C., 30° C., or 35° C. at a thickness of 3.2 mm according toASTM D 256-10.

The cross-linkable polycarbonates of the present disclosure may have anotched Izod impact strength (NII) of greater than or equal to 500 J/m,greater than or equal to 550 J/m, greater than or equal to 600 J/m,greater than or equal to 650 J/m, greater than or equal to 700 J/m,greater than or equal to 750 J/m, greater than or equal to 800 J/m,greater than or equal to 850 J/m, greater than or equal to 900 J/m,greater than or equal to 950 J/m, or greater than or equal to 1000 J/m,measured at 23° C. according to ASTM D 256.

The cross-linkable polycarbonates of the present disclosure may have aheat distortion temperature of greater than or equal to 110° C., 111°C., 112° C., 113° C., 114° C., 115° C., 116° C., 117° C., 118° C., 119°C., 120° C., 121° C., 122° C., 123° C., 124° C., 125° C., 126° C., 127°C., 128° C., 129° C., 130° C., 131° C., 132° C., 133° C., 134° C., 135°C., 136° C., 137° C., 138° C., 139° C., 140° C., 141° C., 142° C., 143°C., 144° C., 145° C., 146° C., 147° C., 148° C., 149° C., 150° C., 151°C., 152° C., 153° C., 154° C., 155° C., 156° C., 157° C., 158° C., 159°C., 160, 161° C., 162° C., 163° C., 164° C., 165° C., 166° C., 167° C.,168° C., 169° C., or 170° C., as measured according to ASTM D 648 at1.82 MPa, with 3.2 mm thick unannealed mm bar.

The cross-linkable polycarbonates of the present disclosure may have apercent haze value of less than or equal to 10.0%, less than or equal to8.0%, less than or equal to 6.0%, less than or equal to 5.0%, less thanor equal to 4.0%, less than or equal to 3.0%, less than or equal to2.0%, less than or equal to 1.5%, less than or equal to 1.0%, or lessthan or equal to 0.5% as measured at a certain thickness according toASTM D 1003-07. The polycarbonate haze may be measured at a 2.0, 2.2,2.4, 2.54, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, or a 4.0 millimeterthickness. The polycarbonate may be measured at a 0.125 inch thickness.

The polycarbonate may have a light transmittance greater than or equalto 50%, greater than or equal to 60%, greater than or equal to 65%,greater than or equal to 70%, greater than or equal to 75%, greater thanor equal to 80%, greater than or equal to 85%, greater than or equal to90%, greater than or equal to 95%, greater than or equal to 96%, greaterthan or equal to 97%, greater than or equal to 98%, greater than orequal to 99%, greater than or equal to 99.1%, greater than or equal to99.2%, greater than or equal to 99.3%, greater than or equal to 99.4%,greater than or equal to 99.5%, greater than or equal to 99.6%, greaterthan or equal to 99.7%, greater than or equal to 99.8%, or greater thanor equal to 99.9%, as measured at certain thicknesses according to ASTMD 1003-07. The polycarbonate transparency may be measured at a 2.0, 2.2,2.4, 2.6, 2.8, 3.0, 3.2, 3.4, 3.6, 3.8, or a 4.0 millimeter thickness.

In certain embodiments, the cross-linkable polycarbonates of the presentdisclosure do not include soft block or soft aliphatic segments in thepolycarbonate chain. For example, the following aliphatic soft segmentsthat may be excluded from the cross-linkable polycarbonates of thepresent disclosure include aliphatic polyesters, aliphatic polyethers,aliphatic polythioethers, aliphatic polyacetals, aliphaticpolycarbonates, C—C linked polymers and polysiloxanes. The soft segmentsof aliphatic polyesters, aliphatic polyethers, aliphatic polythioethers,aliphatic polyacetals, aliphatic polycarbonates may be characterized ashaving Number Average MWs (Mns) of greater than 600.

In certain embodiments, the cross-linkable polycarbonates of the presentdisclosure do not include units derived from aromatic di-, tri-, ortetrahydroxyketones.

In certain embodiments, the cross-linkable polycarbonates of the presentdisclosure do not include units derived from dihydroxybenzophenonemonomers, trihydroxybenzophenone monomers, tetrahydroxybenzophenonemonomers, or other multiple-hydroxybenzophenone monomers. For example,the following monomer units may be excluded from use in thecross-linkable and cross-linked polycarbonates of the presentdisclosure: 4,4′-dihydroxybenzophenone, 2,4-dihydroxybenzophenone, and4-(α,α-bis(4-hydroxyphenyl)ethyl-benzophenone.

In particular embodiments, the photoactive additive is anon-cross-linked (i.e. cross-linkable) polycarbonate having thestructure of Formula (I):

wherein R¹ and R² are independently halogen, C₁₋₆ alkyl, C₃₋₈cycloalkyl, aryl, or arylalkyl; x is an integer from 0 to 4; y is aninteger from 0 to 5; n′ is an integer from 29 to 65; and the repeatingunit W is derived from:(i) a monomer having the structure:HO-A₁-Y₁-A₂-OHwherein each of A₁ and A₂ comprise a monocyclic divalent arylene group,and Y₁ is a bridging group having one or more atoms; or(ii) a monomer having the structure:

each R^(k) is independently halogen, a C₁₋₁₀ hydrocarbon group, or ahalogen substituted C₁₋₁₀ hydrocarbon group; and n is 0 to 4. In moreparticular embodiments, the repeating unit W is derived frombisphenol-A.

In more specific embodiments, the non-cross-linked (i.e. cross-linkable)polycarbonate has the structure of Formula (II):

wherein n′ ranges from 29 to 65.

In particular embodiments, the photoactive cross-linkable polycarbonatecontains about 0.5 mol % of endcaps derived from amonohydroxybenzophenone, and has a weight-average molecular weight (Mw)from 17,000 to 30,000 Daltons. In other specific embodiments, thephotoactive cross-linkable polycarbonate contains about 2.5 mol % ofendcaps derived from a monohydroxybenzophenone, and has a weight-averagemolecular weight (Mw) from 24,000 to 31,000 Daltons. In still otherdefinite embodiments, the photoactive cross-linkable polycarbonate hasan MVR of 8 to 10 cc/10 min at 300° C./1.2 kg/360 sec dwell, and canachieve UL94 V0 performance at a thickness of 2.0 mm.

An interfacial polycondensation polymerization process for bisphenol-A(BPA) based polycarbonates can be used to prepare the photoactiveadditives (PAAs) of the present disclosure. Although the reactionconditions for interfacial polymerization can vary, an exemplary processgenerally involves dissolving or dispersing one or more dihydric phenolreactants (e.g. bisphenol-A) in aqueous caustic soda or potash, addingthe resulting mixture to a water-immiscible solvent medium, andcontacting the reactants with a carbonate precursor (e.g. phosgene) inthe presence of a catalyst (e.g. triethylamine, TEA) under controlled pHconditions, e.g., 8 to 11.

Four different interfacial processes are disclosed herein for producingsome embodiments of the photoactive additive which contain carbonatelinkages. Each process includes the following ingredients: a monohydroxycompound, a polyhydroxy compound, a carbonate precursor, a tertiaryamine catalyst, water, and a water-immiscible organic solvent. Themonohydroxy compound is the photoactive moiety. It should be noted thatmore than one of each ingredient can be used to produce the photoactiveadditive. For example, both bisphenol-A and trishydroxyphenylethane(THPE) would be considered polyhydroxy compounds (though one is a diolchain extender and the other is a branching agent). Some information oneach ingredient is first provided below.

The monohydroxy compound is the photoactive moiety previously described.For example, the monohydroxy compound can have the structure of any oneof Formulas (1), (3), or (5)-(10). The monohydroxy compound acts as anendcapping agent, and the previously described endcapping agents (e.g.p-cumyl phenol) could also be used. If desired, more than onemonohydroxy compound can be used. In particular embodiments forproducing a cross-linkable polycarbonate, the monohydroxy compound is amonohydroxybenzophenone of Formula (1).

The term “polyhydroxy compound” here refers to a compound having two ormore hydroxyl groups. In contrast, the term “dihydroxy compound” refersto a compound having only two hydroxyl groups. The polyhydroxy compoundcan be a dihydroxy compound having the structure of any one of Formulas(B)-(H), which are chain extenders, and include monomers such asbisphenol-A. In addition, the secondary linker moieties of any one ofFormulas (43)-(49) can be considered a polyhydroxy compound, and areuseful as branching agents. If desired, more than one polyhydroxycompound can be used. See, for example, the reaction in FIG. 5. In thecross-linkable polycarbonates of the present disclosure, bisphenol-A istypically used.

The carbonate precursor may be, for example, a carbonyl halide such ascarbonyl dibromide or carbonyl dichloride (also known as phosgene), or ahaloformate such as a bishaloformate of a dihydric phenol (e.g., thebischloroformate of bisphenol-A, hydroquinone, or the like) or a glycol(e.g., the bishaloformate of ethylene glycol, neopentyl glycol,polyethylene glycol, or the like). Combinations comprising at least oneof the foregoing types of carbonate precursors can also be used. Incertain embodiments, the carbonate precursor is phosgene, a triphosgene,diacyl halide, dihaloformate, dicyanate, diester, diepoxy,diarylcarbonate, dianhydride, dicarboxylic acid, diacid chloride, or anycombination thereof. An interfacial polymerization reaction to formcarbonate linkages may use phosgene as a carbonate precursor, and isreferred to as a phosgenation reaction. Many such carbonate precursorscorrespond to a structure of Formulas (30)-(35).

A tertiary amine catalyst is used for polymerization. Exemplary tertiaryamine catalysts that can be used are aliphatic tertiary amines such astriethylamine (TEA), tributylamine, cycloaliphatic amines such asN,N-diethyl-cyclohexylamine and aromatic tertiary amines such asN,N-dimethylaniline.

Sometimes, a phase transfer catalyst is also used. Among the phasetransfer catalysts that can be used are catalysts of the formula(R³⁰)₄Q⁺X, wherein each R³⁰ is the same or different, and is a C₁-C₁₀alkyl group; Q is a nitrogen or phosphorus atom; and X is a halogenatom, C₁-C₈ alkoxy group, or C₆-C₁₈ aryloxy group. Exemplary phasetransfer catalysts include, for example, [CH₃(CH₂)₃]₄NX, [CH₃(CH₂)₃]₄PX,[CH₃(CH₂)₅]₄NX, [CH₃(CH₂)₆]₄NX, [CH₃(CH₂)₄]₄NX, CH₃[CH₃(CH₂)₃]₃NX, andCH₃[CH₃(CH₂)₂]₃NX, wherein X is Cl⁻, Br⁻, a C₁-C₈ alkoxy group or aC₆-C₁₈ aryloxy group.

The most commonly used water-immiscible solvents include methylenechloride, 1,2-dichloroethane, chlorobenzene, toluene, and the like.

In the first process, sometimes referred to as the “upfront” process,all of the hydroxy compounds, catalysts, water, and water-immisciblesolvent are combined upfront in a vessel to form a reaction mixture. Thereaction mixture is then exposed to the carbonate precursor, for exampleby phosgenation, to obtain the photoactive additive.

In the second process, also known as the “solution addition” process,the polyhydroxy compound(s), tertiary amine catalyst, water, andwater-immiscible solvent are combined in a vessel to form a reactionmixture. The carbonate precursor is then added to this reaction mixturein the vessel over a first time period. During this time period, themonohydroxy compound is added in a controlled manner to the reactionmixture as well, also referred to as programmed addition. The additionof the monohydroxy compound occurs throughout the first time period,rather than as a bolus at one time point (as in the upfront process).The photoactive additive is thus obtained.

The third process is also referred to as a bis-chloroformate (BCF)process. Bischloroformate oligomers are prepared by reacting thecarbonate precursor, specifically phosgene, with the polyhydroxycompound(s) in the absence of the tertiary amine catalyst. After thebischloroformate oligomers are generated, the monohydroxy compound isadded to the chloroformate mixture. The reaction is allowed to proceed,and the tertiary amine catalyst is added to complete the reaction.

The fourth process uses a tubular reactor. In the tubular reactor, themonohydroxy compound is pre-reacted with the carbonate precursor(specifically phosgene) to form chloroformates. The water-immisciblesolvent is used as a solvent in the tubular reactor. In a separatereactor, the polyhydroxy compound, tertiary amine catalyst, water, andwater-immiscible solvent are combined to form a reaction mixture. Thechloroformates in the tubular reactor are then fed into the reactor overa first time period along with additional carbonate precursor tocomplete the reaction.

The resulting photoactive additive (e.g. the cross-linkablepolycarbonate) contains only a small amount of low-molecular-weightcomponents. This can be measured in two different ways: the level ofdiarylcarbonates and the lows percentage can be measured.Diarylcarbonates are formed by the reaction of twomonohydroxybenzophenones with phosgene, creating a small molecule thatcontains no chain extender (e.g. bisphenol-A). In embodiments, theresulting photoactive additive contains less than 1900 ppm ofdiarylcarbonates. In more specific embodiments, the photoactive additivecontains less than 700 ppm, or about 100 ppm or less ofdiarylcarbonates. The lows percentage is the percentage by weight ofoligomeric chains having a molecular weight of less than 1000. Inembodiments, the lows percentage is 2.0 wt % or less, or 1.5 wt % orless, including from about 1.0 wt % to 1.5 wt %, or from about 1.0 wt %to 1.7 wt %, or from about 1.0 wt % to 2.0 wt %. Also of note is thatthe resulting photoactive additive does not contain any residualpyridine, because pyridine is not used in the manufacture of thephotoactive additive.

The ratio of the polydispersity index (PDI) measured using a UV detectorto the PDI measured using an RI detector may be 1.8 or less, when usinga GPC method and polycarbonate molecular weight standards, or may be 1.5or less, or 1.2 or less.

The photoactive additive (PAA) can be blended with one or more polymericbase resins by melt blending or solution blending to form a polymericcomposition/blend. The PAA-containing blend can be then be formed intoan article by a variety of known processes such as solution casting,profile extrusion, film and/or sheet extrusion, sheet-foam extrusion,injection molding, blow molding, thermoforming, and the like.

The article is then exposed to ultraviolet (UV) light at an appropriatewavelength and in an appropriate dosage that brings about the desiredamount of crosslinking for the given application. Depending on the enduse application and the desired properties, the UV exposure can beperformed on one or more sides of the article.

The article where the enhanced properties are needed should be exposedwith a substantially uniform dose of UV light. The exposure can beaccomplished using standard methods known in the art. For example, theUV light can come from any source of UV light such as, but not limitedto, those lamps powered by microwave, HID lamps, and mercury vaporlamps. In some other embodiments, the article is exposed by usingnatural sunlight. The exposure time will be dependent on the applicationand color of material. It can range from a few minutes to several days.Alternatively, the crosslinking can be accomplished by using aUV-emitting light source such as a mercury vapor, High-IntensityDischarge (HID), or various UV lamps. For example, commercial UV lampsare sold for UV curing from manufacturers such as Hereaus Noblelight andFusion UV. Non-limiting examples of UV-emitting light bulbs includemercury bulbs (H bulbs), or metal halide doped mercury bulbs (D bulbs,H+ bulbs, and V bulbs). Other combinations of metal halides to create aUV light source are also contemplated. Exemplary bulbs could also beproduced by assembling the lamp out of UV-absorbing materials andconsidered as a filtered UV source. A mercury arc lamp is not used forirradiation. An H bulb has strong output in the range of 200 nm to 320nm. The D bulb has strong output in the 320 nm to 400 nm range. The Vbulb has strong output in the 400 nm to 420 nm range.

It can be beneficial to control the temperature. Often increasedtemperature can increase the crosslinking, but if the temperature isexcessive the article can become unacceptably discolored, warped, ordistorted.

It may also be advantageous to use a UV light source where the harmfulwavelengths (those that cause polymer degradation or excessiveyellowing) are removed or not present. Equipment suppliers such asHeraeus Noblelight and Fusion UV provide lamps with various spectraldistributions. The light can also be filtered to remove harmful orunwanted wavelengths of light. This can be done with optical filtersthat are used to selectively transmit or reject a wavelength or range ofwavelengths. These filters are commercially available from a variety ofcompanies such as Edmund Optics or Praezisions Glas & Optik GmbH.Bandpass filters are designed to transmit a portion of the spectrum,while rejecting all other wavelengths. Longpass edge filters aredesigned to transmit wavelengths greater than the cut-on wavelength ofthe filter. Shortpass edge filters are used to transmit wavelengthsshorter than the cut-off wavelength of the filter. Various types ofmaterials, such as borosilicate glass, can be used as a long passfilter. Schott and/or Praezisions Glas & Optik GmbH for example have thefollowing long pass filters: WG225, WG280, WG295, WG305, WG320 whichhave cut-on wavelengths of ˜225, 280, 295, 305, and 320 nm,respectively. These filters can be used to screen out the harmful shortwavelengths while transmitting the appropriate wavelengths for thecrosslinking reaction. In particular embodiments, when a 1.6 mm bar ismade and exposed to UV radiation, then placed for 48 hours at 23° C. inthe dark, the crosslinked bar has a delta YI after 48 hours of 4 orless.

In particular embodiments, the article is exposed to a selected UV lightrange having wavelengths from about 280 nanometers (nm) to about 380 nm,or from about 330 nm to about 380 nm, or from about 280 nm to about 360nm, or from about 330 nm to about 360 nm. The wavelengths in a“selected” light range have an internal transmittance of greater than50%, with wavelengths outside of the range having an internaltransmittance of less than 50%. The change in transmittance may occurover a range of 20 nm. Reference to a selected light range should not beconstrued as saying that all wavelengths within the range transmit at100%, or that all wavelengths outside the range transmit at 0%.

UV wavelengths can be separated into four different categories. UVArefers to wavelengths from 320 nm to 390 nm. UVB refers to wavelengthsfrom 280 nm to 320 nm. UVC refers to wavelengths from 250 nm to 260 nm.UVV refers to wavelengths from 395 nm to 445 nm. In various embodiments,the total UV energy to which the surface of the formed article isexposed is calculated as the sum of the energy from UVA, UVB, and UVClight irradiated over a set period of time, and is about from about 40J/cm² to about 50 J/cm², including about 45 J/cm².

A high quality crosslinked layer in an article is a layer which has thedesired crosslinked layer thickness; desired cross-linked density(higher crosslink density may afford better chemical resistance, but mayalso lead to lower toughness); a lower level of color shift; a lowerlevel of warp and article distortion; and/or a low level of resindegradation from harmful UV radiation. A high quality crosslinked layerand article is achieved by selecting UV light that induces crosslinkingwhile minimizing the UV light wavelengths which induce degradation andcolor formation of the composition.

The exposed article will have a cross-linked outer surface and an innersurface that is either lightly cross-linked or not cross-linked. Theouter surface can be cross-linked to such a degree that the outersurface is substantially insoluble in the common solvents for thestarting resins. The percentage of the insolubles will be dependent onthe part geometry and surface-to-volume ratio, but will generally befrom 2% to 95%. For a ⅛″ ASTM Izod bar exposed on one side, thepercentage of insoluble will be from 1% to 75%. For most ⅛″ articlesexposed on one side, the insolubles will be from 2% to 10%.

The amount of PAA added to the blend can be used to fine-tune the finalproperties of the article. For example, articles requiring high chemicalresistance and FR drip inhibition would need increased PAA content. Ingeneral, depending on the application, the overall molar percentage ofthe PAA should be from 0.5 mole % to 15 mole %, based on the weight ofthe polymeric resin. In more specific applications, the overallpercentage is from 1 mole % to 10 mole %.

Second Polymer Resin

The PAAs can be blended with a polymeric base resin that is differentfrom the photoactive additive, i.e. a second polymer resin, to form thepolymeric compositions/blends of the present disclosure. Morespecifically, the second polymer resin does not contain photoactivegroups. In embodiments, the weight ratio of the photoactive additive tothe polymeric base resin is from 1:99 to 99:1, including from about50:50 to about 85:15. The polymeric base resin has, in specificembodiments, a weight-average molecular weight of about 21,000 orgreater, including from about 21,000 to about 40,000.

The PAAs are suitable for blending with polycarbonate homopolymers,polycarbonate copolymers, and polycarbonate blends. They are alsosuitable for blending with polyesters, polyarylates,polyestercarbonates, and polyetherimides.

The blends may comprise one or more distinct cross-linkablepolycarbonates, as described herein, and/or one or more cross-linkedpolycarbonates, as described herein, as the photoactive additive. Theblends also comprise one or more additional polymers. The blends maycomprise additional components, such as one or more additives. Incertain embodiments, a blend comprises a cross-linkable and/orcross-linked polycarbonate (Polymer A) and a second polymer (Polymer B),and optionally one or more additives. In another embodiment, a blendcomprises a combination of a cross-linkable and/or cross-linkedpolycarbonate (Polymer A); and a second polycarbonate (Polymer B),wherein the second polycarbonate is different from the firstpolycarbonate.

The second polymer (Polymer B) may be any polymer different from thefirst polymer that is suitable for use in a blend composition. Incertain embodiments, the second polymer may be a polycarbonate, apolyester, a polysiloxane-co-bisphenol-A polycarbonate, apolyesteramide, a polyimide, a polyetherimide, a polyamideimide, apolyether, a polyethersulfone, a polyepoxide, a polylactide, apolylactic acid (PLA), or any combination thereof.

In certain embodiments, the polymeric base resin may be a vinyl polymer,a rubber-modified graft copolymer, an acrylic polymer,polyacrylonitrile, a polystyrene, a polyolefin, a polyester, apolyesteramide, a polysiloxane, a polyurethane, a polyamide, apolyamideimide, a polysulfone, a polyepoxide, a polyether, a polyimide,a polyetherimide, a polyphenylene ether, a polyphenylene sulfide, apolyether ketone, a polyether ether ketone, an ABS resin, an ASA resin,a polyethersulfone, a polyphenylsulfone, a poly(alkenylaromatic)polymer, a polybutadiene, a polyacetal, a polycarbonate, a polyphenyleneether, an ethylene-vinyl acetate copolymer, a polyvinyl acetate, aliquid crystal polymer, an ethylene-tetrafluoroethylene copolymer, anaromatic polyester, a polyvinyl fluoride, a polyvinylidene fluoride, apolyvinylidene chloride, tetrafluoroethylene, a polylactide, apolylactic acid (PLA), a polycarbonate-polyorganosiloxane blockcopolymer, or a copolymer comprising: (i) an aromatic ester, (ii) anestercarbonate, and (iii) carbonate repeat units. The blend compositionmay comprise additional polymers (e.g. a third, fourth, fifth, sixth,etc., polymer).

In certain embodiments, the polymeric base resin may be ahomopolycarbonate, a copolycarbonate, a polycarbonate-polysiloxanecopolymer, a polyester-polycarbonate, or any combination thereof. Incertain embodiments, the polymeric base resin is a p-cumyl phenol cappedpoly(isophthalate-terephthalate-resorcinol ester)-co-(bisphenol-Acarbonate) copolymer. In certain embodiments, the polymeric base resinis a polycarbonate-polysiloxane copolymer.

The p-cumyl phenol capped poly(isophthalate-terephthalate-resorcinolester)-co-(bisphenol-A carbonate) polymer or apolycarbonate-polysiloxane copolymer may have a polysiloxane contentfrom 0.4 wt % to 25 wt %. In one preferred embodiment, the polymericbase resin is a p-cumylphenol capped poly(19 mol %isophthalate-terephthalate-resorcinol ester)-co-(75 mol % bisphenol-Acarbonate)-co-(6 mol resorcinol carbonate) copolymer (MW=29,000Daltons). In another preferred embodiment, the polymeric base resin is ap-cumylphenol capped poly(10 wt % isophthalate-terephthalate-resorcinolester)-co-(87 wt % bisphenol-A carbonate)-co-(3 mol % resorcinolcarbonate) copolymer (MW=29,000 Daltons).

In another preferred embodiment, the polymeric base resin is apolycarbonate polysiloxane copolymer. The polycarbonate-polysiloxanecopolymer may be a siloxane block co-polycarbonate comprising from about6 wt % siloxane (±10%) to about 20 wt % siloxane (±10%) and having asiloxane chain length of 10 to 200. In another preferred embodiment, thepolymeric base resin is a PC-siloxane copolymer with 20% siloxanesegments by weight. In another preferred embodiment, the polymeric baseresin is a p-cumylphenol capped poly(65 mol % BPA carbonate)-co-(35 mol% 3,3-bis(4-hydroxyphenyl)-2-phenylisoindolin-1-one (PPPBP) carbonate)copolymer (MW=25,000 Daltons).

In another preferred embodiment, the polymeric base resin is apolyphosphonate polymer, a polyphosphonate copolymer, or apoly(polyphosphonate)-co-(BPA carbonate) copolymer.

In yet other embodiments, the polymeric base resin is selected from thegroup consisting of a polycarbonate-polysiloxane copolymer; apolycarbonate resin having an aliphatic chain containing at least twocarbon atoms as a repeating unit in the polymer backbone; anethylene-acrylic ester-glycidyl acrylate terpolymer; a polyethyleneterephthalate polymer; a bisphenol-A homopolymer; a polystyrene polymer;a poly(methyl methacrylate) polymer; a thermoplastic polyester; apolybutylene terephthalate polymer; a methylmethacrylate-butadiene-styrene copolymer; anacrylonitrile-butadiene-styrene copolymer; or a dimethyl bisphenolcyclohexane-co-bisphenol-A copolymer.

Other conventional additives can also be added to the polymericcomposition (e.g. an impact modifier, UV stabilizer, colorant, flameretardant, heat stabilizer, plasticizer, lubricant, mold release agent,filler, reinforcing agent, antioxidant agent, antistatic agent, blowingagent, anti-drip agent, or radiation stabilizer).

In a preferred embodiment, the blend compositions disclosed hereincomprise a flame-retardant/anti-drip agent, a flame retardant additive,and/or an impact modifier. The flame-retardant/anti-drip agent may bepotassium perfluorobutane sulfonate (Rimar salt), potassium diphenylsulfone-3-sulfonate (KSS), or a combination thereof.

Various types of flame retardants can be utilized as additives. In oneembodiment, the flame retardant additives include, for example, flameretardant salts such as alkali metal salts of perfluorinated C₁-C₁₆alkyl sulfonates such as potassium perfluorobutane sulfonate (Rimarsalt), potassium perfluoroctane sulfonate, tetraethylammoniumperfluorohexane sulfonate, potassium diphenylsulfone sulfonate (KSS),and the like, sodium benzene sulfonate, sodium toluene sulfonate (NATS)and the like; and salts formed by reacting for example an alkali metalor alkaline earth metal (for example lithium, sodium, potassium,magnesium, calcium and barium salts) and an inorganic acid complex salt,for example, an oxo-anion, such as alkali metal and alkaline-earth metalsalts of carbonic acid, such as Na₂CO₃, K₂CO₃, MgCO₃, CaCO₃, and BaCO₃or fluoro-anion complex such as Li₃AlF₆, BaSiF₆, KBF₄, K₃AlF₆, KAlF₄,K₂SiF₆, and/or Na₃AlF₆ or the like. Rimar salt and KSS and NATS, aloneor in combination with other flame retardants, are particularly usefulin the compositions disclosed herein. In certain embodiments, the flameretardant does not contain bromine or chlorine.

The flame retardant optionally is a non-halogen based metal salt, e.g.,of a monomeric or polymeric aromatic sulfonate or mixture thereof. Themetal salt is, for example, an alkali metal or alkali earth metal saltor mixed metal salt. The metals of these groups include sodium, lithium,potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium,francium and barium. Examples of flame retardants include cesiumbenzenesulfonate and cesium p-toluenesulfonate. See e.g., U.S. Pat. No.3,933,734, EP 2103654, and US2010/0069543A1, the disclosures of whichare incorporated herein by reference in their entirety.

Another useful class of flame retardant is the class of cyclic siloxaneshaving the general formula [(R)₂SiO]_(y), wherein R is a monovalenthydrocarbon or fluorinated hydrocarbon having from 1 to 18 carbon atomsand y is a number from 3 to 12. Examples of fluorinated hydrocarboninclude, but are not limited to, 3-fluoropropyl, 3,3,3-trifluoropropyl,5,5,5,4,4,3,3-heptafluoropentyl, fluorophenyl, difluorophenyl andtrifluorotolyl. Examples of suitable cyclic siloxanes include, but arenot limited to, octamethylcyclotetrasiloxane,1,2,3,4-tetramethyl-1,2,3,4-tetravinylcyclotetrasiloxane,1,2,3,4-tetramethyl-1,2,3,4-tetraphenylcyclotetrasiloxane,octaethylcyclotetrasiloxane, octapropylcyclotetrasiloxane,octabutylcyclotetrasiloxane, decamethylcyclopentasiloxane,dodecamethylcyclohexasiloxane, tetradecamethylcycloheptasiloxane,hexadecamethylcyclooctasiloxane, eicosamethylcyclodecasiloxane,octaphenylcyclotetrasiloxane, and the like. A particularly useful cyclicsiloxane is octaphenylcyclotetrasiloxane.

Exemplary heat stabilizer additives include, for example,organophosphites such as triphenyl phosphite,tris-(2,6-dimethylphenyl)phosphite, tris-(mixed mono- anddi-nonylphenyl)phosphite or the like; phosphonates such asdimethylbenzene phosphonate or the like; phosphates such as trimethylphosphate, or the like; or combinations comprising at least one of theforegoing heat stabilizers. Heat stabilizers are generally used inamounts of 0.0001 to 1 part by weight, based on 100 parts by weight ofthe polymer component of the polymeric blend/composition.

Mold release agent (MRA) will allow the material to be removed quicklyand effectively. Mold releases can reduce cycle times, defects, andbrowning of finished product. There is considerable overlap among thesetypes of materials, which may include, for example, phthalic acid esterssuch as dioctyl-4,5-epoxy-hexahydrophthalate;tris-(octoxycarbonylethyl)isocyanurate; tristearin; di- orpolyfunctional aromatic phosphates such as resorcinol tetraphenyldiphosphate (RDP), the bis(diphenyl)phosphate of hydroquinone and thebis(diphenyl)phosphate of bisphenol-A; poly-alpha-olefins; epoxidizedsoybean oil; silicones, including silicone oils; esters, for example,fatty acid esters such as alkyl stearyl esters, e.g., methyl stearate,stearyl stearate, pentaerythritol tetrastearate (PETS), and the like;combinations of methyl stearate and hydrophilic and hydrophobic nonionicsurfactants comprising polyethylene glycol polymers, polypropyleneglycol polymers, poly(ethylene glycol-co-propylene glycol) copolymers,or a combination comprising at least one of the foregoing glycolpolymers, e.g., methyl stearate and polyethylene-polypropylene glycolcopolymer in a suitable solvent; waxes such as beeswax, montan wax,paraffin wax, or the like. Such materials are generally used in amountsof 0.001 to 1 part by weight, specifically 0.01 to 0.75 part by weight,more specifically 0.1 to 0.5 part by weight, based on 100 parts byweight of the polymer component of the polymeric blend/composition.

In particular embodiments, the polymeric blend/composition includes thephotoactive additive, an optional polymeric base resin, and a flameretardant which is Rimar salt and which is present in an amount of about0.05 wt % to about 0.085 wt %, based on the total weight of thecomposition; and a plaque comprising the polymeric composition has atransparency of 70 to 90% at a thickness of 3.2 mm, measured accordingto ASTM-D1003-00.

In other particular embodiments, the polymeric blend/compositionincludes the photoactive additive, an optional polymeric base resin, aflame retardant; a heat stabilizer, and a mold release agent.

One advantage of using the PAAs with polymeric resins is that polymerswith relatively higher Mw's generally retain their mechanical propertiesbetter, while polymers with relatively lower Mw's generally have betterflow properties. The PAAs can be used to produce complex or thin moldedarticles that are difficult to mold using higher molecular weightpolymers. Upon irradiation of the molded article, crosslinks can beformed that extend the molecular weight and improve physical propertiessuch as impact strength, tensile strength, flame retardance, or chemicalresistance.

The polymeric blend can improve the chemical resistance of the finalmolded article. It is contemplated that molded articles can be of anydesired shape (e.g. film, sheet, etc.) and be used in many differentapplications, for example in the medical, automotive, and consumerelectronics fields. Increased chemical resistance may be found against409 Glass and Surface Cleaner; Alcohol Prep Pad; CaviCideliquid/CaviWipes; CaviWipes; Cidex Plus liquid; Clorox Bleach; CloroxWipes; Envirocide liquid; ForPro liquid; Gentle dish soap and water;Hydrogen Peroxide Cleaner Disinfectant Wipes; Isopropyl Alcohol wipes;MadaCide-1 liquid; Mar-V-Cide liquid to dilute; Sani-Cloth Bleach Wipes;Sani-Cloth HB Wipes; Sani-Cloth Plus Wipes; Sodium Hypochlorite liquid;Super Sani-Cloth Wipes; Viraguard liquid and Wipes; Virex 256; WindexBlue; Fuel C; Toluene; Heptane; Ethanol; Isopropanol; Windex; Engineoil; WD40; Transmission fluid; Break fluid; Glass wash; Diesel;Gasoline; Banana Boat Sunscreen (SPF 30); Sebum; Ivory Dish Soap; SCJohnson Fantastik Cleaner; French's Yellow Mustard; Coca-Cola; 70%Isopropyl Alcohol; Extra Virgin Olive Oil; Vaseline Intensive Care HandLotion; Heinz Ketchup; Kraft Mayonnaise; Chlorox Formula 409 Cleaner; SCJohnson Windex Cleaner with Ammonia; Acetone; Artificial Sweat; Fruits &Passion Cucina Coriander & Olive Hand Cream; Loreal Studioline MegagelHair Gel; Maybelline Lip Polish; Maybelline Expert Wear Blush—Beach PlumRouge; Purell Hand Sanitizer; Hot coffee, black; iKlear; Chlorox Wipes;Squalene; Palmitic Acid; Oleic Acid; Palmitoleic Acid; Stearic Acid; andOlive Oil.

Articles

Compositions/blends disclosed herein, preferably prior to cross-linking,may be formed, shaped, molded, injection molded, or extruded into anarticle. The compositions/blends can be molded into useful shapedarticles by a variety of means such as injection molding, overmolding,co-injection molding, extrusion, multilayer extrusion, rotationalmolding, blow molding and thermoforming to form articles. The formedarticles may be subsequently subjected to cross-linking conditions(e.g., UV-radiation) to affect cross-linking of the polycarbonatescomprising monohydroxybenzophenone derived endcap. Exemplary articlesinclude a film, a sheet, a layer of a multilayer film, or a layer of amultilayer sheet.

Articles that may be formed from the compositions/blends include variouscomponents for cell phones and cell phone covers, components forcomputer housings (e.g. mouse covers), fibers, computer housings andbusiness machine housings and parts such as housings and parts formonitors, computer routers, copiers, desk top printers, largeoffice/industrial printers handheld electronic device housings such ascomputer or business machine housings, housings for hand-held devices,components for light fixtures or home or office appliances, humidifierhousings, thermostat control housings air conditioner drain pans,outdoor cabinets, telecom enclosures and infrastructure, Simple Networkintrusion Detection System (SNIDS) devices, network interface devices,smoke detectors, components and devices in plenum spaces, components formedical applications or devices such as medical scanners, X-rayequipment, and ultrasound devices, components for interior or exteriorcomponents of an automobile, lenses (auto and non-auto) such ascomponents for film applications, greenhouse components, sun roomcomponents, fire helmets, safety shields, safety goggles, glasses withscratch resistance and impact resistance, fendors, gas pumps, films fortelevisions, such as ecofriendly films having no halogen content, solarapplication materials, glass lamination materials, fibers forglass-filled systems, hand held electronic device enclosures or parts(e.g. walkie-talkie, scanner, media/MP3/MP4 player, radio, GPS system,ebook, tablet), wearable electronic devices (e.g. smart watch,training/tracking device, activity/sleep monitoring system, wristband,or glasses), hand held tool enclosures or parts, smart phone enclosuresor parts, turbine blades (e.g., wind turbines), and the like.

In certain embodiments, articles that may comprise the composition/blendinclude automotive bumpers, other automotive, construction andagricultural equipment exterior components, automobile mirror housings,an automobile grille, an automobile pillar, automobile wheel covers,automobile, construction and agricultural equipment instrument panelsand trim, construction and agricultural grilles, automobile glove boxes,automobile door hardware and other interior trim, automobileconstruction and agricultural equipment exterior lights, automobileparts within the engine compartment, plumbing equipment, valves andpumps, air conditioning heating and cooling parts, furnace and heat pumpparts, computer parts, electronics parts, projector parts, electronicdisplay parts, copier parts, scanner parts, electronic printer tonercartridges, hair driers, irons, coffee makers, toasters, washingmachines, microwaves, ovens, power tools, electric components, lightingparts, dental instruments and equipment, medical instruments, cookware,medical instrument trays, animal cages, fibers, laser welded medicaldevices, hand held electronic device enclosures or parts (e.g.walkie-talkie, scanner, media/MP3/MP4 player, radio, GPS system, ebook,tablet), wearable electronic devices (e.g. smart watch,training/tracking device, activity/sleep monitoring system, wristband,or glasses), hand held tool enclosures or parts, smart phone enclosuresor parts, and fiber optics.

In certain embodiments, articles that may comprise the composition/blendinclude automotive bumpers, other automotive exterior components,automobile mirror housings, an automobile grille, an automobile pillar,automobile wheel covers, automobile instrument panels and trim,automobile glove boxes, automobile door hardware and other interiortrim, external automobile trim parts, such as pillars, automobileexterior lights, automobile parts within the engine compartment, anagricultural tractor or device part, a construction equipment vehicle ordevice part, a construction or agricultural equipment grille, a marineor personal water craft part, an all terrain vehicle or all terrainvehicle part, plumbing equipment, valves and pumps, air conditioningheating and cooling parts, furnace and heat pump parts, computer parts,electronics parts, projector parts, electronic display parts, copierparts, scanner parts, electronic printer toner cartridges, hair driers,irons, coffee makers, toasters, washing machines, microwaves, ovens,power tools, electric components, electric enclosures, lighting parts,dental instruments, medical instruments, medical or dental lightingparts, an aircraft part, a train or rail part, a seating component,sidewalls, ceiling parts, cookware, medical instrument trays, animalcages, fibers, laser welded medical devices, fiber optics, lenses (autoand non-auto), cell phone parts, greenhouse components, sun roomcomponents, fire helmets, safety shields, safety glasses, gas pumpparts, hand held electronic device enclosures or parts (e.g.walkie-talkie, scanner, media/MP3/MP4 player, radio, GPS system, ebook,tablet), wearable electronic devices (e.g. smart watch,training/tracking device, activity/sleep monitoring system, wristband,or glasses), hand held tool enclosures or parts, smart phone enclosuresor parts, and turbine blades.

In certain embodiments, the article is one that requires or must includea material having a UL94 5VA rating performance. Articles that require aUL94 5VA rating include, but are not limited to, computer housings,computer housings and business machine housings and parts such ashousings and parts for monitors, computer routers, copiers, desk topprinters, large office/industrial printers, handheld electronic devicehousings such as computer or business machine housings, housings forhand-held devices, components for light fixtures including LED fixturesor home or office appliances, humidifier housings, thermostat controlhousings, air conditioner drain pans, outdoor cabinets, telecomenclosures and infrastructure, Simple Network Intrusion Detection System(SNIDS) devices, network interface devices, smoke detectors, componentsand devices in plenum spaces, components for medical applications ordevices such as medical scanners, X-ray equipment, and ultrasounddevices, electrical boxes and enclosures, and electrical connectors.

In certain embodiments, the article is one that requires hydrothermalstability, such as a wind turbine blade, a steam sterilizable medicaldevice, a food service tray, utensiles and equipment.

In certain embodiments, the article is one that requires a combinationof transparency, flame resistance, and/or impact resistance. Forexample, in certain embodiments the article may be a safety shield,safety goggles, a gas/fuel pump housing, a display window or part, orthe like.

The following examples are provided to illustrate the polymericcompositions/blends, articles, processes and properties of the presentdisclosure. The examples are merely illustrative and are not intended tolimit the disclosure to the materials, conditions, or process parametersset forth therein.

EXAMPLES

All solvents and reagents used were analytical grade.

Molecular weight determinations were performed using gel permeationchromatography (GPC), using a cross-linked styrene-divinylbenzene columnand calibrated to polycarbonate references using a UV detector set at264 nm. Samples were prepared at a concentration of about 1 mg/ml, andeluted at a flow rate of about 1.0 ml/min.

Differential scanning calorimetry (DSC) employing a temperature sweeprate of 20° C./min was used to determine glass transition temperaturesof polycarbonates.

(A) Preparation of Cross-Linkable Polycarbonates

Example 1 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—0.5 mol %—23 k”

The following were added into a 2 liter glass reactor equipped with anoverhead condenser, a phosgene inlet and a pH probe allowing monitoringpH during the course of the reaction: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (30 g, 131.6 mmol); (b)4-hydroxybenzophenone (0.13 g, 0.7 mmol); (c) para-cumylphenol (0.7 g,3.3 mmol); (d) triethylamine (0.18 g, 1.3 mmol); (e) methylene chloride(500 mL); (f) de-ionized water (300 mL). The reaction was allowed tostir for 10 minutes and the pH was maintained at pH=8 by the addition of30 wt-% NaOH solution. The mixture was charged with phosgene (18.6 g, 2g/min, 0.188 mol). During the addition of phosgene, base (30 wt-% NaOH)was simultaneously charged to the reactor to maintain the pH of thereaction between 9-10. After the complete addition of phosgene, thereaction was purged with nitrogen gas, and the organic layer wasseparated. The organic extract was washed once with dilute hydrochloricacid (HCl), and subsequently washed with de-ionized water three times.The organic layer was precipitated from methylene chloride into hotwater. The polymer was dried in an oven at 110° C. before analysis. Gelpermeation chromatography (GPC) allowed for a determination of themolecular weight of the resulting polymer. The Mw of the polycarbonatewas measured to be 22,877 Daltons (referenced to polycarbonatestandards) and polydispersity index=3.11.

Example 2 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—2.5 mol %—30 k”

The following were added into a 2 liter glass reactor equipped with anoverhead condenser, a phosgene inlet and a pH probe allowing monitoringpH during the course of the reaction: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (30 g, 131.6 mmol); (b)4-hydroxybenzophenone (0.65 g, 3.3 mmol); (c) para-cumylphenol (0.14 g,0.7 mmol); (d) triethylamine (0.18 g, 1.3 mmol); (e) methylene chloride(500 mL); (f) de-ionized water (300 mL). The reaction was allowed tostir for 10 minutes and the pH was maintained at pH=8 by the addition of30 wt-% NaOH solution. The mixture was charged with phosgene (18.74 g, 2g/min, 0.189 mol). During the addition of phosgene, base (30 wt-% NaOH)was simultaneously charged to the reactor to maintain the pH of thereaction between 9-10. After the complete addition of phosgene, thereaction was purged with nitrogen gas, and the organic layer wasseparated. The organic extract was washed once with dilute hydrochloricacid (HCl), and subsequently washed with de-ionized water three times.The organic layer was precipitated from methylene chloride into hotwater. The polymer was dried in an oven at 110° C. before analysis. Gelpermeation chromatography (GPC) allowed for a determination of themolecular weight of the resulting polymer. The Mw of the polycarbonatewas measured to be 30,255 Daltons (referenced to polycarbonatestandards) and polydispersity index=2.09.

Example 3 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—1.7 mol %—28 k”

The following were added into a 70 L continuous stirred-tank reactor(CSTR) equipped with an overhead condenser and a recirculation pump witha flow rate of 40 L/minute: (a) 4,4-bis-(hydroxyphenyl)-2,2-propane(BPA) (4000 g, 17.52 mol); (b) 4-hydroxybenzophenone (59 g, 0.297 mol);(c) para-cumylphenol (45 g, 0.212 mol); (d) triethylamine (42 mL, 0.415mol); (e) methylene chloride (23.4 L); (f) de-ionized water (10.8 L),and (g) sodium gluconate (10 g). The reaction was allowed to stir for 10minutes and the pH was maintained at pH=9 by the addition of 30% NaOHsolution. The mixture was charged with phosgene (2500 g, 80 g/min, 25.3mol). During the addition of phosgene, base (30 wt % NaOH) wassimultaneously charged to the reactor to maintain the pH of the reactionbetween 8.5-9. After the complete addition of phosgene, the reaction waspurged with nitrogen gas, and the organic layer was separated. Theorganic extract was washed once with dilute hydrochloric acid (HCl), andsubsequently washed with de-ionized water three times. The organic layerwas precipitated from methylene chloride into hot steam. The polymer wasdried in an oven at 110° C. before analysis. The Mw of the polycarbonatewas measured to be 28,366 Daltons (referenced to polycarbonatestandards) and polydispersity index=3.78.

Example 4 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—2.5 mol %—27 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (87 g, 0.438 mol); (c) para-cumylphenol (28 g,0.132 mol); (d) triethylamine (60 mL, 0.593 mol); (e) methylene chloride(23 L); (f) de-ionized water (10 L), and (g) sodium gluconate (10 g).The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2500 g, 80 g/min, 25.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be27,106 Daltons (referenced to polycarbonate standards) andpolydispersity index=6.19.

Example 5 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—0.5 mol %—28 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (18 g, 0.09 mol); (c) para-cumylphenol (105 g,0.494 mol); (d) triethylamine (60 mL, 0.593 mol); (e) methylene chloride(23 L); (f) de-ionized water (10 L), and (g) sodium gluconate (10 g).The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2500 g, 80 g/min, 25.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be27,482 Daltons (referenced to polycarbonate standards) andpolydispersity index=3.40.

Example 6 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—0.5 mol %—24 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (18 g, 0.09 mol); (c) para-cumylphenol (120 g,0.565 mol); (d) triethylamine (60 mL, 0.593 mol); (e) methylene chloride(23 L); (f) de-ionized water (10 L), and (g) sodium gluconate (10 g).The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2500 g, 80 g/min, 25.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be24,379 Daltons (referenced to polycarbonate standards) andpolydispersity index=3.30.

Example 7 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—0.5 mol %—21 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (18 g, 0.09 mol); (c) para-cumylphenol (148 g,0.697 mol); (d) triethylamine (60 mL, 0.593 mol); (e) methylene chloride(24.4 L); (f) de-ionized water (10.8 L), and (g) sodium gluconate (10g). The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2500 g, 80 g/min, 25.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be21,171 Daltons (referenced to polycarbonate standards) andpolydispersity index=3.22.

Example 8 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—2.5 mol %—26 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (87 g, 0.438 mol); (c) para-cumylphenol (35 g,0.165 mol); (d) triethylamine (80 mL, 0.79 mol); (e) methylene chloride(23 L); (f) de-ionized water (10 L), and (g) sodium gluconate (10 g).The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2700 g, 80 g/min, 27.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be25,916 Daltons (referenced to polycarbonate standards) andpolydispersity index=5.21.

Example 9 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—0.5 mol %—27 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (18 g, 0.09 mol); (c) para-cumylphenol (105 g,0.49 mol); (d) triethylamine (60 mL, 0.59 mol); (e) methylene chloride(23 L); (f) de-ionized water (10 L), and (g) sodium gluconate (10 g).The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2700 g, 80 g/min, 27.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be27,055 Daltons (referenced to polycarbonate standards) andpolydispersity index=3.19.

Example 10 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—0.5 mol %—27 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (18 g, 0.09 mol); (c) para-cumylphenol (148 g,0.698 mol); (d) triethylamine (42 mL, 0.41 mol); (e) methylene chloride(23 L); (f) de-ionized water (10 L), and (g) sodium gluconate (10 g).The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2700 g, 80 g/min, 27.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be27,256 Daltons (referenced to polycarbonate standards) andpolydispersity index=3.23.

Example 11 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—2.5 mol %—26 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (87 g, 0.439 mol); (c) para-cumylphenol (35 g,0.165 mol); (d) triethylamine (42 mL, 0.41 mol); (e) methylene chloride(23 L); (f) de-ionized water (10 L), and (g) sodium gluconate (10 g).The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2700 g, 80 g/min, 27.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be25,999 Daltons (referenced to polycarbonate standards) andpolydispersity index=6.98.

Example 12 4-Hydroxybenzophenone Endcapped Polycarbonate“Benzophenone-BPA Copolymer—2.5 mol %—27 k”

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 g, 17.52 mol); (b)4-hydroxybenzophenone (87 g, 0.439 mol); (c) para-cumylphenol (28 g,0.132 mol); (d) triethylamine (42 mL, 0.41 mol); (e) methylene chloride(23 L); (f) de-ionized water (10 L), and (g) sodium gluconate (10 g).The reaction was allowed to stir for 10 minutes and the pH wasmaintained at pH=9 by the addition of 30% NaOH solution. The mixture wascharged with phosgene (2700 g, 80 g/min, 27.3 mol). During the additionof phosgene, base (30 wt % NaOH) was simultaneously charged to thereactor to maintain the pH of the reaction between 8.5-9. After thecomplete addition of phosgene, the reaction was purged with nitrogengas, and the organic layer was separated. The organic extract was washedonce with dilute hydrochloric acid (HCl), and subsequently washed withde-ionized water three times. The organic layer was precipitated frommethylene chloride into hot steam. The polymer was dried in an oven at110° C. before analysis. The Mw of the polycarbonate was measured to be27,084 Daltons (referenced to polycarbonate standards) andpolydispersity index=7.26.

Table 1 summarizes the constituents and the weight average molecularweights of the polycarbonates of Examples 1-12.

TABLE 1 Component Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Ex. 6 Ex. 7 BPA (kg)0.03 0.03 4 4 4 4 4 HBP (g) 0.13 0.65 59 87 18 18 18 PCP (g) 0.7 0.14 4528 105 120 148 Na glu (g) — — 10 10 10 10 10 NEt₃ (mL) 0.18 g  0.18 g 4260 60 60 60 Phosgene (kg) 18.6 g 18.74 g 2.5 2.5 2.5 2.5 2.5 Water (L)0.3 0.3 10.8 10 10 10 10.8 CH₂Cl₂ (L) 0.5 0.5 23.4 23 23 23 24.4 Mw,Daltons 22,877 30,255 28,366 27,106 27,482 24,379 21,171 PDI — — 3.786.19 3.40 3.30 3.22 mol % HBP 0.5% 2.5% 1.7% 2.5% 0.5% 0.5% 0.5% endcapComponent Ex. 8 Ex. 9 Ex. 10 Ex. 11 Ex. 12 BPA (kg) 4 4 4 4 4 HBP (g) 8718 18 87 87 PCP (g) 35 105 148 35 28 Na glu (g) 10 10 10 10 10 NEt₃ (mL)80 60 60 42 42 Phosgene (kg) 2.7 2.7 2.7 2.7 2.7 Water (L) 10 10 10 1010 CH₂Cl₂ (L) 23 23 23 23 23 Mw, Daltons 25,916 27,055 27,256 25,99927,084 PDI 5.21 3.19 3.23 6.98 7.26 mol % HBP 2.5% 0.5% 0.5% 2.5% 2.5%endcap BPA = bisphenol-A; HBP = 4-hydroxybenzophenone; PCP =p-cumylphenol; Na glu = sodium gluconate; NEt₃ = triethylamine; CH₂Cl₂ =methylene chloride; PDI = polydispersity index

The 4-hydroxybenzophenone endcapped polycarbonates of Examples 1-12 wereprepared as compositions optionally using one or more of the componentsshown in Table 2. Comparative Examples were also prepared using thecomponents of Table 2. The referenced compositions were prepared bymixing together the selected constituents and preblending. Extrusion andmolding was carried out under normal polycarbonate processingconditions.

TABLE 2 Trade name, Component Description Source 20:80 ITR- Poly(19 mol% isophthalate- SABIC-IP PC terephthalate-resorcinol ester)-co- (75 mol% bisphenol- A carbonate)-co-(6 mol % resorcinol carbonate) copolymer(Mw = 31,000, PC standards) HF-PC Bisphenol-A based SABIC-IP orpolycarbonate High-Flow resin (Mw = 22,000 PC Daltons, PC standards)LF-PC Bisphenol-A based SABIC-IP or polycarbonate resin Low-Flow (Mw =30,000 PC Daltons, PC standards) KSS Potassium Arichemdiphenylsulphon-3-sulphonate LLC Rimar Salt Potassium Lanxessperfluorobutanesulfonate PETS pentaerythritol tetrastearate Faci UVstabilizer 2-(2'-hydroxy-5'-t-octylphenyl) CYASORB benzotriazole UV5411, Cytec Heat Tetrakis(2,4-di-tert- PEPQ, stabilizerbutylphenyl)-4,4’- Ciba biphenylenediphosphonite Specialty ChemicalsHydrolytic Cycloaliphatic Epoxy Resin, ERL4221, stabilizer 3,4-epoxycyclohexyl Various methyl-3,4-epoxy cyclohexyl carboxylate Colorant 1Colorant 2 Phosphite Tris (2,4-di-tert-butylphenyl) Irgaphos Stabilizerphosphite 168 Hindered Phenol

(B) Cross-Linking Results

Compositions of the 4-hydroxybenzophenone endcapped polycarbonates ofExamples 1-12 were cross-linked with ultra-violet (UV) radiation. Thepolycarbonate compositions were treated with ultra-violet radiationgenerated from a UV-lamp, or irradiative energy (including UV) receivedupon sun exposure.

(i) Cross-Linking of 4-Hydroxybenzophenone Endcapped PolycarbonatesUsing a UV-Lamp

Ultra-violet radiation was used to cross-link the neat resincompositions of Examples 1 and 2. First, films of Examples 1 and 2 wereformed by melt-pressing the corresponding powder at 550° F. Thethickness of each film was about 0.5 mm. Each film was then irradiatedwith UV-radiation emitted from a 9 mm D bulb having outputspecifications of about 796.5 Watts from 201 nm to 600 nm, as shown inTable 3. The film was placed on a conveyor belt having a total cycletime of 90 seconds per pass through the UV system, with the irradiationtime being 20 seconds, providing an energy of irradiation of 3,000mJ/cm² measured using an EIT UV Power Puck™ aletro-optic radiometer.

TABLE 3 Interval (nm) Power (Watts) 201-210 2.3 211-220 4.2 221-230 4.9231-240 5.8 241-250 10.8 251-260 17.7 261-270 13.6 271-280 20.3 281-29011.6 291-300 24.3 301-310 28.6 311-320 21.5 321-330 21.0 331-340 11.0341-350 24.4 351-360 50.8 361-370 57.5 371-380 74.9 381-390 72.2 391-40027.9 401-410 30.6 411-420 26.2 421-430 34.8 431-440 40.4 441-450 19.5451-460 4.9 461-470 3.5 471-480 2.7 481-490 9.0 491-500 15.3 501-510 7.2511-520 12.7 521-530 16.7 531-540 17.2 541-550 27.3 551-560 5.3 561-5703.8 571-580 8.7 581-590 3.4 591-600 2.2

Table 4 demonstrates the progression of molecular weight as a functionof irradiation time of Example 1 and Example 2. These data show that themolecular weight of each film increased dramatically as a function of UVdosage. The data shows also that the more 4-hydroxybenzophenone endcappresent in the resin, the greater is the molecular weight increase, asExample 2 (2.5 mol % HBP endcap) showed a 144% increase in molecularweight after 5 passes under the UV-lamp, compared with a 30% increase inmolecular weight for Example 1 (0.5 mol % HBP endcap) after 5 passes.

TABLE 4 Unit Example 1 Example 2 4-Hydroxybenzophenone mol-% 0.5 2.5amount Untreated film MW Daltons 22,877 30,255 1 pass UV-treated film MWDaltons 25,784 53,346 5 pass UV-treated film MW Daltons 29,664 73,945 MWincrease after 5 passes % 30 144

FIG. 17 and FIG. 18 also demonstrate the progression of molecular weightas a function of irradiation time for 4-hydroxybenzophenone endcappedpolycarbonates of the invention. The figures show molecular weightprogression upon cross-linking of 4-hydroxybenzophenone-BPApolycarbonates at 0.5 mol % hydroxybenzophenone endcap, 1.5 mol %hydroxybenzophenone endcap, and 2.5 mol % hydroxybenzophenone endcap.Each of the three polycarbonates included sufficient p-cumylphenolendcap to bring the total endcap mol % to 3 mol %.

The cross-linking reaction of Example 2 (benzophenone-BPA copolymer—2.5mol %—30 k) was monitored by ¹H-nuclear magnetic resonance spectroscopy(NMR), as shown in FIG. 19 and FIG. 20. Without being bound by theory,it is believed that cross-linking occurs between benzophenone carbonylcarbon atoms and methyl carbon atoms as found in repeating bisphenol-Aunits. The cross-linking reaction can be monitored by following the peakintensity increase at 3.48 ppm in the NMR spectrum of the composition,which peak corresponds to the methylene hydrogens at the newly formedcarbon-carbon bond. FIG. 19 and FIG. 20 illustrate that with each passunder the UV-lamp, the peak intensity increased at 3.48 ppm, indicatingprogression of the cross-linking process.

(ii) Cross-Linking of 4-Hydroxybenzophenone Endcapped Polycarbonates ViaSun Exposure

Sun exposure was used to cross-link the polycarbonates. Films wereformed of the cross-linkable polycarbonates by melt-pressing thecorresponding powder at 550° F. The thickness of each film was about 0.5mm. Each film was then exposed to UV-radiation emitted from the sun overa period of 360 hours.

Table 5, shown below, and FIG. 21 demonstrate that upon exposure toirradiative energy from the sun, the 4-hydroxybenzophenone endcappedpolycarbonates underwent cross-linking and an increase in molecularweight. Accordingly, sun exposure can be used as a method ofcross-linking the herein disclosed polycarbonates comprisingmonohydroxybenzophenone derived endcaps.

The % Gel data indicates the extent of crosslinking as function of thesun exposure time. The % Gel is measured by dividing the dry weight ofthe crosslinked portion of the exposed material by the total weight ofthe sample. The crosslinked portion corresponds to the insoluble part ofthe sample soaked in methylene chloride for 12 hours. This data showsthat higher the amount of HBP, greater will be the amount of crosslinkedmaterial after sun exposure.

TABLE 5 Sun Exposure Time (Hours) Delta HBP 0 4 24 48 72 144 360 MW %(%) MW MW MW MW MW MW MW (%) Gel 0.5 21620 25900 25098 25324 25703 2620226013 16 0 0.5 26118 31130 33305 36826 32371 35363 34994 28 1 0.5 2754931145 34172 36231 34756 36235 36517 24 1 2.5 25458 41086 59852 6074560224 69605 78980 135 15 2.5 24245 46183 79350 65228 67150 45841 58211227 27 2.5 26145 45112 64941 51008 63437 63819 34831 148 52 HBP =hydroxybenzophenone; MW = Molecular Weight

(C) Flame Resistance

Flammability tests were performed following the procedure ofUnderwriter's Laboratory Bulletin 94 entitled “Tests for Flammability ofPlastic Materials, UL94”. Several ratings can be applied based on therate of burning, time to extinguish, ability to resist dripping, andwhether or not drips are burning. According to this procedure, materialsmay be classified as HB, V0, V1, V2, 5V, 5VA and/or 5VB on the basis ofthe test results obtained for five samples of a given thickness. It isassumed that a material that meets a given standard at a given thicknesscan also meet the same standard at greater thicknesses (e.g. a materialthat obtains V0 performance at 1.5 mm thickness can also obtain V0performance at 2.0 mm thickness, 2.5 mm, etc.). The criteria for theflammability classifications or “flame retardance” are described below.

V0: A specimen is supported in a vertical position and a flame isapplied to the bottom of the specimen. The flame is applied for tenseconds and then removed until flaming stops at which time the flame isreapplied for another ten seconds and then removed. Two sets of fivespecimens are tested. The two sets are conditioned under differentconditions.

To achieve a V0 rating, specimens must not burn with flaming combustionfor more than 10 seconds after either test flame application. Totalflaming combustion time must not exceed 50 seconds for each set of 5specimens. Specimens must not burn with flaming or glowing combustion upto the specimen holding clamp. Specimens must not drip flaming particlesthat ignite the cotton. No specimen can have glowing combustion remainfor longer than 30 seconds after removal of the test flame

5VA: Testing is done on both bar and plaque specimens. Procedure forBars: A bar specimen is supported in a vertical position and a flame isapplied to one of the lower corners of the specimen at a 20° angle. Theflame is applied for 5 seconds and is removed for 5 seconds. The flameapplication and removal is repeated five times. Procedure for Plaques:The procedure for plaques is the same as for bars except that the plaquespecimen is mounted horizontally and a flame is applied to the center ofthe lower surface of the plaque.

To achieve a 5VA rating, specimens must not have any flaming or glowingcombustion for more than 60 seconds after the five flame applications.Specimens must not drip flaming particles that ignite the cotton. Plaquespecimens must not exhibit burnthrough (a hole).

V1: In a sample placed so that its long axis is 180 degrees to theflame, the average period of flaming and/or smoldering after removingthe igniting flame does not exceed twenty-five seconds and, for a V-1rating, none of the vertically placed samples produces drips of burningparticles that ignite absorbent cotton.

Compositions comprising cross-linked polycarbonates disclosed herein(neat and blended) were evaluated for UL 94 V0 and 5VA performance ascompared to high-flow BPA-polycarbonate neat and blended compositions.The tested compositions and flame test results are provided in Tables6-9, shown below.

(i) V0 Performance

Flammability testing was conducted on flame bars prepared fromcompositions labelled as Sample 1 (S1), Comparative Sample 2 (CS2),Sample 3 (S3), and Comparative Sample 4 (CS4), described in Table 6. 51is a blend composition comprising the benzophenone-BPA copolymer ofExample 8 and a p-cumylphenol capped poly(20 wt %isophthalate-terephthalate-resorcinol ester)-co-(80 wt % bisphenol-Acarbonate) copolymer. CS2 is a blend composition comprising a high-flowBPA-polycarbonate and a p-cumylphenol capped poly(20 wt %isophthalate-terephthalate-resorcinol ester)-co-(80 wt % bisphenol-Acarbonate) copolymer. S3 is a neat resin composition comprising thebenzophenone-BPA copolymer of Example 8. CS4 is a neat resin compositioncomprising the high-flow BPA-polycarbonate.

TABLE 6 Sample Ingredient Unit S1 CS2 S3 CS4 Example 8 Benzophenone-BPAcopolymer - pbw 55 100 2.5 mol-% - 26k 20:80 p-cumylphenol cappedpoly(20 wt % pbw 45 45 ITR-PC isophthalate-terephthalate-resorcinolester)-co-(80 wt % bisphenol-A carbonate) copolymer (Mw = 60,000, PSstandards) HF-PC Bisphenol-A based polycarbonate resin pbw 55 100 (Mw =22,000 Daltons, PS standards) UV 2-(2′-hydroxy-5′-t- phr 0.20 0.20 0.200.20 stabilizer octylphenyl)benzotriazole PEPQ Phosphonous Acid Esterphr 0.06 0.06 0.06 0.06 Powder (CAS # 119345-01-6) Cycloaliphatic EpoxyResin (3,4-epoxy phr 0.03 0.03 0.03 0.03 cyclohexyl methyl-3,4-epoxycyclohexyl carboxylate), ERL4221 KSS Potassiumdiphenylsulphon-3-sulphonate phr 0.03 0.03 0.03 0.03 PETSpentaerythritol tetrastearate phr 0.30 0.30 0.30 0.30 Colorant 1 phr0.13 0.13 0.13 0.13 Colorant 2 phr 0.13 0.13 0.13 0.13 MVR Melt VolumeFlow Rate cc/10 9.5 15.9 8.1 25.9 min Abusive Abusive Melt Volume FlowRate cc/10 11.4 21.7 8.5 27.7 MVR min

Flammability testing was conducted using the standard UnderwritersLaboratory UL 94 test method (7 day conditioning), except that 20 barsrather than the usual 5 bars were tested. Specimens are to bepreconditioned either at room temperature for 48 hours or in anair-circulating oven for 168 hours at 70±1° C. and then cooled in adesiccator for at least 4 hours at room temperature, prior to testing.Once removed from the desiccator, specimens are tested within 30minutes.

The data was also analyzed by calculating the average flame out time,standard deviation of the flame out time and the total number of drips,and by using statistical methods to convert that data to a prediction ofthe probability of first time pass, or “pFTP”, that a particular sampleformulation would achieve a “pass” rating in the conventional UL94 V0 orV1 testing of 5 bars. The probability of a first time pass on a firstsubmission (pFTP) may be determined according to the formula:pFTP=(P _(t1>mbt,n=0) ×P _(t2>mbt,n=0) ×P _(total<=mtbt)×_(P drip,n=0))where P_(t1>mbt, n=0) is the probability that no first burn time exceedsa maximum burn time value, P_(t2>mbt, n=0) is the probability that nosecond burn time exceeds a maximum burn time value, P_(total<=mtbt) isthe probability that the sum of the burn times is less than or equal toa maximum total burn time value, and P_(drip, n=0) is the probabilitythat no specimen exhibits dripping during the flame test. First andsecond burn time refer to burn times after a first and secondapplication of the flame, respectively.

The probability that no first burn time exceeds a maximum burn timevalue, P_(t1>mbt, n=0), may be determined from the formula:P_(t1>mbt, n=0)=(1-P_(t1>mbt))⁵ where P_(t1>mbt) is the area under thelog normal distribution curve for t1>mbt, and where the exponent “5”relates to the number of bars tested. The probability that no secondburn time exceeds a maximum burn time value may be determined from theformula: P_(t2>mbt, n=0)=(1-P_(t2>mbt)) where P_(t2>mbt) is the areaunder the normal distribution curve for t2>mbt. As above, the mean andstandard deviation of the burn time data set are used to calculate thenormal distribution curve. For the UL-94 V-0 rating, the maximum burntime is 10 seconds. For a V-1 or V-2 rating the maximum burn time is 30seconds. The probability P_(drip, n=0) that no specimen exhibitsdripping during the flame test is an attribute function, estimated by:(1-P_(drip))⁵ where P_(drip)=(the number of bars that drip/the number ofbars tested).

The probability P_(total<=mtbt) that the sum of the burn times is lessthan or equal to a maximum total burn time value may be determined froma normal distribution curve of simulated 5-bar total burn times. Thedistribution may be generated from a Monte Carlo simulation of 1000 setsof five bars using the distribution for the burn time data determinedabove. Techniques for Monte Carlo simulation are well known in the art.A normal distribution curve for 5-bar total burn times may be generatedusing the mean and standard deviation of the simulated 1000 sets.Therefore, P_(total<=mtbt) may be determined from the area under a lognormal distribution curve of a set of 1000 Monte Carlo simulated 5-bartotal burn time for total<=maximum total burn time. For the UL94 V0rating, the maximum total burn time is 50 seconds. For a V1 rating, themaximum total burn time is 250 seconds.

Preferably, p(FTP) values will be 1 or very close to 1 for highconfidence that a sample formulation would achieve a given rating in UL94 testing (e.g. V0). However, it should be noted that, for example, asample formulation may pass the V0 performance test and have a lowpFTP(V0) rating, because the pFTP is a probability.

Table 7 presents pFTP values for the blend (S1) comprising thebenzophenone-BPA copolymer and the p-cumylphenol capped ITR-PC; and theneat benzophenone-BPA copolymer (S3). p(FTP) values are provided forboth before and after the flame bars are exposed to UV radiation. Theresults from S1 and S3 are compared with results from flame barsprepared from the blend (CS2) comprising the high-flow BPA polycarbonateand the p-cumylphenol capped ITR-PC; and the neat high-flowBPA-polycarbonate (CS4). S3 and CS4 were prepared in order to comparethe flame behavior of the blends of S1 and CS2 with neat resincompositions. Potassium sulfone sulfonate was incorporated into thetested compositions as a flame poison.

TABLE 7 Sample S1 CS2 S3 CS4 (blend) (blend) (neat) (neat) Flame(HBP-BPA/ITR- (HF-BPA/ITR- (HBP- (HF- Resistance PC) PC) BPA) BPA)Before p(FTP) @ 0 0 0 0 UV 2.00 mm After UV p(FTP) @ 0.99 0 0.8 0 2.00mm p(FTP) @ 0.2 0 0.3 — 1.50 mm p(FTP) @ 0.1 0 — — 1.00 mm HBP-BPA =Benzophenone-BPA copolymer - 2.5 mol-% - 26k; HF-BPA = High-FlowBisphenol-A based polycarbonate resin; HBP-BPA/ITR-PC = Benzophenone-BPAcopolymer - 2.5 mol-% - 26k/p-cumylphenol capped poly(20 wt %isophthalate-terephthalate-resorcinol ester)-co-(80 wt % bisphenol-Acarbonate) copolymer; HF-BPA/ITR-PC = High-Flow Bisphenol-A basedpolycarbonate resin/p-cumylphenol capped poly(20 wt %isophthalate-terephthalate-resorcinol ester)-co-(80 wt % bisphenol- Acarbonate) copolymer.

The data of Table 7 shows a dramatic increase of the p(FTP) values forthe UV-treated compositions incorporating 4-hydroxybenzophenone endcap,whereas the corresponding controls with the high-flow polycarbonate donot show any variation in their respective probability values.Surprisingly, even in blends, the cross-linked benzophenone-BPAcopolymers impart V0 performance to the test bars at 2 mm thickness.

(ii) 5VA Performance

Flammability testing was conducted on flame bars and plaques preparedfrom compositions labelled as Sample 5 (S5), Comparative Sample 6 (CS6),Sample 7 (S7), and Comparative Sample 8 (CS8), described in Table 8. S5is a low-flow benzophenone-BPA copolymer composition having a meltvolume flow rate (MVR) of 2.81 cm³/10 minutes at 300° C., 1.2 kg, 360seconds, and an abusive MVR of 2.89 cm³/10 minutes at 300° C., 1.2 kg,1080 seconds. CS6 is a low-flow BPA-polycarbonate composition having anMVR of 6.35 cm³/10 minutes at 300° C., 1.2 kg, 360 seconds, and anabusive MVR of 6.52 cm³/10 minutes at 300° C., 1.2 kg, 1080 seconds. S7is a high-flow benzophenone-BPA copolymer composition having a meltvolume flow rate (MVR) of 11.5 cm³/10 minutes at 300° C., 1.2 kg, 360seconds, and an abusive MVR of 11.7 cm³/10 minutes at 300° C., 1.2 kg,1080 seconds. CS8 is a high-flow BPA-polycarbonate composition having anMVR of 27.6 cm³/10 minutes at 300° C., 1.2 kg, 360 seconds, and anabusive MVR of 27.7 cm³/10 minutes at 300° C., 1.2 kg, 1080 seconds.

TABLE 8 Sample Ingredient Unit S5 CS6 S7 CS8 High-Flow pbw 100Benzophenone-BPA copolymer Low-Flow pbw 100 Benzophenone-BPA copolymerHigh-Flow Bisphenol-A pbw 100 based polycarbonate resin Low-FlowBisphenol-A pbw 100 based polycarbonate resin Potassium phr 0.08 0.080.08 0.08 Perfluorobutane Sulfonate Irgaphos Stabilizer phr 0.06 0.060.06 0.06 Melt Volume cc/10 min 2.81 6.35 11.5 27.6 Flow Rate AbusiveMelt cc/10 min 2.89 6.52 11.7 27.7 Volume Flow Rate

Flammability testing was conducted using the standard UnderwritersLaboratory UL 94 test method (7 day conditioning). 5 bars and 3 plaqueswere tested. Specimens are to be preconditioned in an air-circulatingoven for 168 hours at 70±1° C. and then cooled in a desiccator for atleast 4 hours at room temperature, prior to testing. Once removed fromthe desiccator, specimens are tested within 30 minutes. The data for thebars was analyzed by calculation of the average flame out time, standarddeviation of the flame out time and the total number of drips.Statistical methods were used to convert the data to a probability thata specific formulation would achieve a first time pass or “p(FTP)” inthe standard UL 94 testing of 5 bars. Preferably p(FTP) values will be 1or very close to 1 for high confidence that a sample formulation wouldachieve a 5VA rating in UL 94 testing.

Table 9 presents the 5VA test results for the low-flow and high-flowbenzophenone-BPA copolymer compositions S5 and S7 as compared withlow-flow and high-flow BPA-polycarbonate compositions lackingbenzophenone endcap. The data of Table 9 demonstrates that theUV-treated high-flow and low-flow compositions incorporating4-hydroxybenzophenone endcap (e.g., S5 and S7) can meet 5VA materialrequirements at thicknesses of 2.5 mm or less, 2.0 mm or less, and 1.5mm or less, whereas corresponding controls with the high-flow andlow-flow BPA-polycarbonate (e.g., CS6 and CS8) do not show any variationin their respective flame resistance after UV-treatment. The failure ofUV-treated Sample 7 (S7) at 1.5 mm indicates that endcap mol % andpolymer molecular weight may be balanced to achieve 5VA performance.

TABLE 9 Sample Flame Resistance S5 CS6 S7 CS8 Before UV 5VA @ 3   mm F FF F 5VA @ 2.5 mm F F F F 5VA @ 2   mm F F F F 5VA @ 1.5 mm F F F F AfterUV 5VA @ 2.5 mm P F P F 5VA @ 2   mm P F P F 5VA @ 1.5 mm P F F F P =specimens that passed 5VA testing; F = specimens that failed 5VA testing

The results of Tables 7 and 9 demonstrate that the cross-linkedpolycarbonates disclosed herein, whether neat or within a blendcomposition, impart flame resistance (V0 and 5VA) to articles comprisingthe cross-linked polycarbonates. In particular, the compositions can beused to provide 5VA compliant materials and articles.

The results also demonstrate that even benzophenone-BPA compositionsincorporating UV-absorbing polymers (e.g., p-cumylphenol capped ITR-PC)can undergo sufficient cross-linking to provide compositions thatexhibit V0 and 5VA performance according to UL 94.

The results further demonstrate that 5VA performance can, surprisingly,be achieved using 0.08 wt % or less of a non-brominated, non-chlorinatedflame retardant. This allows preparation of compositions comprising thecross-linked polycarbonates that have high transparency and low hazevalues. In particular, the cross-linked compositions can be used toprovide 5VA compliant materials at 2.5 mm or less, 2 mm or less, and 1.5mm or less, the materials having high transparencies and low hazevalues. In comparison, conventional polycarbonate cannot achieve 5VAperformance without incorporation of significant quantities of flameretardant, which may lower the transparency of the resultingpolycarbonate and effect overall physical properties.

(D) Mechanical and Physical Properties

Improved flame retardance as demonstrated above for the cross-linkedcompositions is generally not useful if the composition also hasexcessive loss of mechanical properties that are needed for end useapplications. As demonstrated below, the cross-linked compositionsretain impact and tensile properties subsequent to UV-treatment.

Table 10 provides mechanical and physical properties of the compositionsof Sample 5 (S5), Comparative Sample 6 (CS6), Sample 7 (S7), andComparative Sample 8 (CS8), the formulations for which are describedabove in Table 8. The properties provided in Table 10 relate to thesamples before UV-treatment. Table 10 shows that the compositions thatincorporate benzophenone endcapped-resin exhibit similar mechanicalproperties to the ones that incorporate conventional BPA-polycarbonateresin.

TABLE 10 Property Sample (before UV-treatment) Unit S5 CS6 S7 CS8Modulus of Elasticity MPa 2354 2332 2388 2372 Tensile Strength at MPa 6466 70.6 68 Break Flexural Modulus MPa 2310 2290 2360 2360 FlexuralModulus — 77.4 53.1 7.36 16.3 Flexural Modulus % 3.35 2.32 0.312 0.692NII Ductility % 100 100 100 100 NII Impact Strength J/m 920 911 845 685HDT ° C. 135.8 133.8 131.5 129.6 MVR cm³/10 min 2.81 6.35 11.5 27.6Abusive MVR cm³/10 min 2.89 6.52 11.7 27.7 NII = Notched Izod Impact;HDT = Heat Distortion Temperature; MVR = Melt Volume Flow Rate

The dynamic oscillatory rheology curves of low-flow benzophenone-BPAcopolymer resin (S5) and low-flow bisphenol-A based polycarbonate resin(CS6) were run on an ARES strain controlled rheometer using a frequencysweep method to determine the viscosity or modulus of the material as afunction of frequency at a constant temperature (300° C.). Frequencysweep measurements were performed using 25 mm parallel-plate geometry ata 20% strain (linear regime) with a fixed gap of 1 mm. The frequency wasvaried from 0.1 to 500 rad/s.

The dynamic oscillatory rheology curve of low-flow bisphenol-A basedpolycarbonate resin is shown in FIG. 22; the dynamic oscillatoryrheology curve of cross-linkable low-flow benzophenone-BPA copolymerresin is shown in FIG. 23. The dynamic oscillatory rheology wasdetermined on pellets of the resins as a function of passes through a UVFusion FS300S with a LC-6B Benchtop Conveyor using a D bulb. The time ofirradiation was ˜90 seconds, providing energy of irradiation of ˜3,000mJ/cm². FIG. 23 shows there is a dramatic increase in the elasticmodulus for the benzophenone capped material. For example, at 0.1 rad/sthe elastic modulus grows from 10 Pa to 10000 Pa (three orders ofmagnitude) from 0 to 5 passes, whereas in the low flow BPApoly-carbonate materials (FIG. 22) the elastic modulus is just 2 Pairrespective of the UV passes. This dramatic increase in elastic modulusas a function UV exposure for the benzophenone capped material materialindicates the formation of crosslinking in the benzophenone end cappedpolycarbonate.

Table 11 shows multiaxial impact (MAI) data for the compositions bothprior to and after UV-exposure. As shown in Table 11, the improved flameresistance of the present compositions comprising cross-linkedpolycarbonate is achieved without significant loss of importantmechanical properties.

TABLE 11 Sample Test (3.2 mm disk) Unit S7 S7 S7 UV-dose mJ/cm² 0 10002000 MAI—Energy to max load J 75.4 62.4 62.9 MAI—Energy to failure J80.5 69.1 67.5 MAI—Energy, Total J 80.5 69.1 67.6 MAI—Max load kN 7.146.653 6.209 MAI—Deflection at max load mm 21.3 19.6 19.9 MAI—Ductility %100 100 100

Table 12 shows that tensile properties of the cross-linked polycarbonatecompositions prepared by sun exposure are not effected by UV exposure.At T₀ (zero hours exposure) the compositions of Sample S5 had anelongation at break of 141.22% (50 mm/min elongation speed). At 168hours, the elongation break was 126.23%. By way of comparison, 100 gr PChad an elongation at break of 119.21% at T₀. Thus, the tensile strengthof the cross-linked compositions is retained after UV-exposure.

TABLE 12 Elongation at Break (%) Sun Exposure (h) Example S5 100 gr PC 0141.22% 119.21% 24 121.08% — 48 123.04% — 168 126.23% —

(E) Chemical Resistance

Compositions comprising cross-linked polycarbonates disclosed hereinwere evaluated for chemical resistance. Powders of4-hydroxybenzophenone-terminated polycarbonates (Examples 3-5),formulated with a phosphite stabilizer and a hindered phenol, were eachstabilized and subsequently pelletized to provide composition samplesS9-S11. The resulting pellets were molded in the form of 3.2 mmcolorchips. Table 13 presents the constituents, the glass transitiontemperature (Tg), and the melt volume flow rate (MVR) for each sample.

TABLE 13 Sample Ingredient Unit S9 S10 S11 Example 3 Benzophenone-BPA wt% 99.89 copolymer - 1.7 mol-% - 28k Example 4 Benzophenone-BPA wt %99.89 copolymer - 2.5 mol-% - 27k Example 5 Benzophenone-BPA wt % 99.89copolymer - 0.5 mol-% - 28k Phosphite Stabilizer wt % 0.06 0.06 0.06Hindered Phenol wt % 0.05 0.05 0.05 Stabilizer MVR Melt Volume cc/10 5.34.8 8.1 Flow Rate min Abusive Abusive cc/10 5.4 5.6 8.6 MVR Melt Volumemin Flow Rate Tg Glass Transition ° C. 151.7 151.7 152.1 Temperature

Colorchips of S9-S11 were plunged into a test fluid for a duration of 5minutes to assess chemical resistance to the fluid. Table 14 shows thechemical resistance of each composition S9-S11 to toluene, acetone, andWindex®. Table 14 shows that higher amounts of 4-hydroxybenzophenoneendcap (e.g., 2.5 mol % as in S10) led to improved chemical resistance,independently of the resin molecular weight. The non-UV treatedcolorchips, when treated with acetone or toluene, exhibitedcrystallization and shrinking on the colorchip surface.

TABLE 14 Sample Chemical Resistance S9 S10 S11 Before UV toluene − − −acetone − − − Windex ® +++ +++ +++ After UV toluene + ++ + acetone +++ + Windex ® +++ +++ +++ “−” = cracking/blistering observed; “+” =lowered gloss observed; “++” = solvent mark observed; “+++” = no visualchange observed

Table 15 shows that UV-irradiated samples S1 and S3, the formulationsfor which are described above in Table 6, are resistant to chemicaltreatment after exposure to UV radiation, as compared to the respectivecontrol samples CS2 and CS4. Surprisingly, even benzophenone-BPA blendsincluding UV-absorbing polymers (e.g., p-cumylphenol capped ITR-PC) suchas that of S1 underwent sufficient cross-linking to provide compositionsthat exhibit extreme chemical resistance (e.g., resistance to acetone).

TABLE 15 Sample S1 CS2 S3 CS4 (blend) (blend) (neat) (neat) Chemical(HBP-BPA/ (HF-BPA/ (HBP- (HF- Resistance ITR-PC) ITR-PC) BPA) BPA)Before toluene − − − − UV acetone − − − − Windex ® +++ +++ +++ +++ AfterUV toluene +++ − +++ − acetone ++ − ++ − Windex ® +++ +++ +++ +++ “−” =cracking/blistering observed; “+” = lowered gloss observed; “++” =solvent mark observed; “+++” = no visual change observed; HBP-BPA =Benzophenone-BPA copolymer - 2.5 mol-% - 26k; HF-BPA = High-FlowBisphenol-A based polycarbonate resin; HBP-BPA/ITR-PC = Benzophenone-BPAcopolymer - 2.5 mol-% - 26k/p-cumylphenol capped poly(20 wt %isophthalate-terephthalate-resorcinol ester)-co-(80 wt % bisphenol-Acarbonate) copolymer; HF-BPA/ITR-PC = High-Flow Bisphenol-A basedpolycarbonate resin/p-cumylphenol capped poly(20 wt %isophthalate-terephthalate-resorcinol ester)-co-(80 wt % bisphenol-Acarbonate) copolymer.

The cross-linked polycarbonate composition S5 was further evaluated forchemical resistance under strain conditions. In a strain jig, fourtensile bars were positioned. The tensile bars were molded at 550° F.barrel temperature, 180° F. mold temperature and 0.5 in/s injectionspeed. Two bars comprised the cross-linked polycarbonate composition S5,and two comprised the S5 composition prior to UV-treatment. Thecurvature of the jig induced a 1% stress level on the tensile bars. Aportion of the bars was exposed to acetone by dripping the solvent ontop of the tensile bars. As shown in Table 16, the tensile bars of thesamples without UV-treatment snapped upon exposure to acetone, whereasthe tensile bars comprised of the cross-linked polycarbonate did notsnap.

TABLE 16 Test Conditions Sample Strain Temperature Exposure Time SolventS5 Before 1% 23° C. Until solvent Acetone Bars snapped UV evaporatesAfter UV 1% 23° C. Until solvent Acetone Bars did not evaporates snap

The chemical resistance results of Tables 14-16 demonstrate that thecross-linked polycarbonates disclosed herein, whether neat or within ablend composition, impart chemical resistance to articles comprising thecross-linked polycarbonate. The results also demonstrate that evenblends with UV-absorbing polymers can achieve sufficient cross-linkingto provide compositions that exhibit extreme chemical resistance.

(F) Haze

Compositions comprising cross-linked polycarbonates disclosed hereinwere evaluated for haze value. Percent haze (% Haze) was determined forthe compositions of samples S5 and S7, the formulations for which aredescribed above in Table 8. The percent haze for each sample was lessthan 2%, the haze value measured on 2.54 mm thick color chips using aColor-Eye 7000A Spectrometer.

Synthesis of Benzophenone-Containing Polycarbonate (BP-PC)

A 4-hydroxybenzophenone (4HBP) end-capped polycarbonate resin (BP-PC)was synthesized as follows.

The following were added into a 70 L CSTR equipped with an overheadcondenser and a recirculation pump with a flow rate of 40 L/minute: (a)4,4-bis-(hydroxyphenyl)-2,2-propane (BPA) (4000 grams, 17.52 moles); (b)4-hydroxybenzophenone (4HBP, 59 grams, 0.297 moles); (c)para-cumylphenol (PCP, 45 grams, 0.212 moles); (d) triethylamine (42 mL,0.415 moles); (e) methylene chloride (23.4 L); (f) de-ionized water(10.8 L), and (g) sodium gluconate (10 grams). The reaction was allowedto stir for 10 minutes and the pH was maintained at pH=9 by the additionof 30% NaOH solution. The mixture was charged with phosgene (2500 grams,80 g/min, 23.3 moles). During the addition of phosgene, base (30 wt %NaOH) was simultaneously charged to the reactor to maintain the pH ofthe reaction between 8.5-9. After the complete addition of phosgene, thereaction was purged with nitrogen gas, and the organic layer wasseparated. The organic extract was washed once with dilute hydrochloricacid (HCl), and subsequently washed with de-ionized water three times.The organic layer was precipitated from methylene chloride into hotsteam. The polymer was dried in an oven at 110 deg C. before analysis.The Mw of the polycarbonate was measured to be 28,366 g/mol (referencedto polycarbonate standards) and polydispersity index=3.78.

Examples 1-5

Table A lists two examples of 4HBP-endcapped polycarbonates (Examples 1and 2). Examples 3 and 4 are polycarbonate controls having PCP endcaps.

TABLE A Name End Cap (Mol %) Mw Mw/Mn Exp 1 4HBP (3.75%) 21,500 3.00 Exp2 4HBP (2.5) 30,500 3.00 Exp 3 PCP (2.5%) 30,000 2.20 Exp 4 PCP (4%)22,500 2.20 Exp 5 4HBP (1.6%) 30,000 3.9

The 4-hydroxybenxzophenone-terminated polycarbonates (XPC) and theirp-cumylphenol controls (PC) are listed in Table A. They were compoundedwith a heat stabilizer, a cyclic siloxane, and Rimar salt (phr) as shownin Table C on a single screw extruder. The samples were then molded into3.2 mm color chips and ASTM Izod bars (0.125 inches×0.5 inches×2.5inches).

TABLE C Name Exp 8 Exp 9 Exp 10 Exp 11 Exp 12 Exp 2 XPC, Mw = 31000100.000 Exp 1 XPC, Mw = 21000 100.000 Exp 3 PC, Mw = 30000 100.000 Exp 4PC, Mw = 22,500 100.000 Exp 5 30,000 MW 1.6 Mol % 4-HBP 100.000 CyclicSiloxane 0.100 0.100 0.100 0.100 0 Potassium Perfluorobutane 0.080 0.0800.080 0.080 0.080 Sulfonate Phosphite stabilizer 0.060 0.060 0.060 0.0600.060

Experiments

FIG. 7 is a graph showing the transmission spectrum for a bisphenol-Apolycarbonate (PC, X symbol) and a bisphenol-A polycarbonate endcappedwith 4-hydroxybenzophenone (EXP 9, triangle). The figure shows theincreased absorption of the benzophenone end groups in the region of 330nm to 380 nm compared to the standard polycarbonate. Also shown in FIG.7 is the spectral distribution of the D Bulb from UV Fusion (asterisk).As seen here, there is significant light being emitted by the D Bulbdown to 200-210 nm, which is can be harmful to polycarbonate. The graphalso shows that borosilicate window glass (5.71 mm thickness, diamond)has a cut-on wavelength of approximately 340 nm (i.e. wavelengths above340 nm have at least 50% transmittance). A LEXAN sheet (square) has aUVA cut-on wavelength of approximately 395 mm. Blocking most of the UVlight below 395 nm would block all the UV light necessary for thecrosslinking reaction. Thus, this LEXAN polycarbonate sheet would beunacceptable as a long pass filter if UV energy was needed. However, itis known in the art to tailor photoinitiators to match the spectraloutput of the light source. In this case, varying the exposure of thephotoactive additive to specific ranges of wavelengths can lead to animproved cross-linked composition that will have the appropriate levelof crosslinking (which can be adjusted by the dose) and lower levels ofresin decomposition by the short wavelengths.

Many 3.2 mm Izod bars were made from the compositions of Examples 8-11.The composition of EXP 12 was molded into 3.2 mm Izod bars and colorchips. These plaques were then exposed to UV-radiation from a D-bulbfrom Fusion UV Systems, Inc. The samples were passed under the lightsource on a UV conveyor system, called here a UV oven, a varying numberof times to provide increasing levels of cross-linking to the surface ofthe samples. The belt speed was set to about 3 feet/min. As the samplesexited the UV oven, they were taken and put back on the belt formultiple passes without lag time until the desired number of passes/dosewas obtained. A UV Power Puck™ from EIT Instruments was first runthrough the UV oven to measure the energy per pass or dose. The dose wasmeasured as the energy from 320-390 nm (UVA), 280-320 nm (UVB), 250-260nm (UVC) and 395-445 nm (UVV). The dose was calculated in J/cm².

The thickness of the crosslinked skin was measured using two differentmethods. First, the average gel content of each plaque was determinedand the skin thickness calculated from that measurement. Second, theskin thickness was measured by optical microscopy.

To measure the amount of cross-linked skin (or gel), four exposed Izodbars were each added to approximately 80 mL of methylene chloride. Thesamples were then gently shaken overnight on a platform shaker. Afterabout 24 hours, the methylene chloride insoluble skins were isolated byfiltration. The samples were then washed with 100 mL of additionalmethylene chloride. To obtain the wt fraction of the insoluble skin, thesamples were filtered using tarred filter paper. After drying thesamples overnight in an oven at 60-80° C., the paper and samples wereweighed. The percentage of insoluble skin was calculated as follows:% Insolubles=100×(wt of the dry insoluble fraction)/wt of the startingbar.

The skin thickness can be estimated by calculating from the % insolubleas follows:Skin Thickness Calculated from Avg % Gel(um)=((3.2 mm×% Gel)/100)×1000microns/mm

To more accurately measure the depth of the cross-linked skin layer,methylene chloride-containing samples were submitted for opticalmicroscopy as follows.

The skin was removed from the methylene chloride using tweezers andplaced onto heavy gauge aluminum foil. Approximately one-fourth toone-half inch was cut out of the middle of the sample using a cleansharp razor blade. This sample was then placed into aluminum pan withsufficient CH₂Cl₂ to cover the section.

The film would often roll up. If the section rolled up and was thickerthan around 10 or 15 microns, the single rolled section was manipulatedwith micro-tools into a configuration of a double rolled section(resembling a scroll). This was then lifted from CH₂Cl₂ by inserting atapered micro-tool into one roll. Then it was placed onto clean aluminumfoil. With a second micro-tool in the other roll of the “scroll”, thetools were slowly pulled apart, rolling the skin out flat onto foil. Thefoil was then folded onto the skin to hold in place (booked) while thesolvent evaporated. A temperature of ˜60-80° C. was applied to speedthis process.

If the film was thinner (less than 10 or 15 microns), the procedure wasmodified by not lifting the film from CH₂Cl₂, but rather allowing mostCH₂Cl₂ to evaporate while the edges of the films are held flat withmicro-tools.

Once the sample was dried, the skin was cut into a narrow (˜500 micron)strip with parallel sides, again utilizing a clean sharp razor blade.This strip was mounted edgewise onto a double-sided carbon or copper SEMtape. Images of the edge of the film strip were then captured via ZeissDiscovery imaging microscope and software. The appropriatemagnification(s) (8.1× to 101×) was selected based on the thickness ofthe film. The cross section thicknesses were captured via the ZeissAxioplan imaging microscope and software.

These results are presented in Table D (see next page).

TABLE D Average Skin # of Thickness Passes Calc. from By Optical SampleUnder UVA UVB UVC UVV Avg. Avg % Gel Microscopy Name UV (J/cm²) (J/cm²)(J/cm²) (J/cm²) % Gel (μm) (μm) EXP 9 0 0 0 0 0 2.3 74 0 EXP 9 2 11 3 05 2.1 66 8 EXP 9 6 33 10 1 15 5.8 184 42 EXP 9 10 53 16 2 24 4.7 152 76EXP 9 15 77 22 3 36 6.0 193 85 EXP 9 20 106 31 4 50 6.9 219 120 EXP 9 25133 40 5 62 7.6 244 116 EXP 11 0 0 0 0 0 1.5 48 No skin EXP 11 2 11 3 05 2.1 67 formed EXP 11 6 33 10 1 15 1.7 55 EXP 11 10 53 16 2 24 2.0 64EXP 11 15 77 22 3 36 1.1 36 EXP 11 20 106 31 4 50 1.5 47 EXP 11 25 13340 5 62 1.5 49 EXP 8 0 0 0 0 0 3.1 99 EXP 8 2 11 3 0 5 2.8 90 EXP 8 6 3310 1 15 3.6 115 EXP 8 10 53 16 2 24 4.5 143 EXP 8 15 77 22 3 36 5.3 169EXP 8 20 106 31 4 50 5.8 184 EXP 8 25 133 40 5 62 6.7 214 EXP 10 0 0 0 00 4.0 128 No skin EXP 10 2 11 3 0 5 1.3 42 formed EXP 10 6 33 10 1 153.2 104 EXP 10 10 53 16 2 24 3.9 126 EXP 10 15 77 22 3 36 2.8 91 EXP 1020 106 31 4 50 2.1 66 EXP 10 25 133 40 5 62 2.7 85 EXP 12 0 0.0 0.0 0.00.0 — — 0.0 EXP 12 2 10.7 3.1 0.4 4.9 0.7 23.0 3.5 EXP 12 10 53.1 15.61.9 24.4 3.5 113.6 31.0

Initially, it should be noted that the unexposed bars (# of passes=0)had average % gel ranging up to 4%. This was attributed to experimentalerror. Presumably non-crosslinked resin was not fully washed off thefilter paper used to determine this value. None of these samples had aninsoluble skin in the methylene chloride solution.

The samples which contained 4HBP (EXP 8 and EXP 9) had an insoluble skinthat remained intact in the methylene chloride solution and could beisolated. The control samples (EXP 10 and EXP 11) did not have an intactinsoluble skin remaining in the methylene chloride layer.

The samples were also measured for delta E against their correspondingunexposed sample within about 2 minutes of exiting the UV oven for thefinal pass. The delta E was again measured after about 24 to 48 hours.These results are reported in Table E (see next page).

TABLE E Average Skin # of Thickness Passes Calc from By Optical Delta EDelta E Sample Under Avg. % Ave % Microscopy after after Name UV Gel Gel(μm) (μm) 2 min 48 hrs EXP 9 0 2.3 74 0 0.0 0.0 EXP 9 2 2.1 66 8 1.5 0.9EXP 9 6 5.8 184 42 4.9 2.5 EXP 9 10 4.7 152 76 5.9 3.2 EXP 9 15 6.0 19385 8.4 4.8 EXP 9 20 6.9 219 120 9.2 5.4 EXP 9 25 7.6 244 116 9.5 5.9 EXP11 0 1.5 48 No skin 0.0 0.0 EXP 11 2 2.1 67 formed 0.5 0.4 EXP 11 6 1.755 0.8 0.8 EXP 11 10 2.0 64 1.3 1.3 EXP 11 15 1.1 36 1.5 1.4 EXP 11 201.5 47 1.8 1.7 EXP 11 25 1.5 49 2.1 2.0 EXP 8 0 3.1 99 0.0 0.0 EXP 8 22.8 90 1.3 0.7 EXP 8 6 3.6 115 3.8 1.9 EXP 8 10 4.5 143 6.2 3.1 EXP 8 155.3 169 7.7 4.2 EXP 8 20 5.8 184 8.3 4.6 EXP 8 25 6.7 214 8.9 5.2 EXP 100 4.0 128 No skin 0.0 0.0 EXP 10 2 1.3 42 formed 0.5 0.4 EXP 10 6 3.2104 0.9 0.6 EXP 10 10 3.9 126 1.1 0.9 EXP 10 15 2.8 91 1.4 1.3 EXP 10 202.1 66 1.7 1.6 EXP 10 25 2.7 85 1.9 1.8 EXP 12 0 0.0 0.0 0.0 EXP 12 20.7 23.0 3.5 1.8 1.2 EXP 12 10 3.5 113.6 31.0 11.3 6.5

This data showed that the color build on exposure to UV light did fade,as shown by the drop in delta E from the 2 min values to the 48 hrvalues.

FIG. 8 is a graph for the results from EXP 9 (Mw≈21,000). The diamondsindicate the % gel vs. UVA energy (left axis), and the squares indicatethe delta E vs. UVA energy.

FIG. 9 is a graph for the results from EXP 8 (Mw≈31,000). The diamondsindicate the % gel vs. UVA energy (left axis), and the squares indicatethe delta E vs. UVA energy.

Both graphs also showed that while increasing the dosage increased the %gel (insoluble cross-linked skin), it also increased the delta E. Formany applications, minimizing the color shift is critical.

Because the % Gel measurement had some error in it, the calculated skinthickness also had some error. However, a plot of the Calculated skinthickness and the Measured skin thickness versus exposure for Exp 9showed a similar but offset trend. This plot is provided as FIG. 10. Thesquares were for calculated skin thickness, while the diamonds were formeasured skin thickness.

The rate of the formation of the skin depth correlated with theconcentration of the photoactive moiety (1.6 mol % vs 3.75 mol %). Thisis seen in FIG. 11. Here, the diamonds are 1.6 mol % 4HBP, and thetriangles are 3.75 mol % 4HBP.

To assess the effectiveness of the cross-linked skin at improving theproperties of the articles, the chemical resistance of the samples toacetone was measured. The color chip samples exposed as shown in Table Dwere exposed to acetone. For the experiment, the samples were exposed onboth sides instead of only one side. After cooling to room temperature,the samples were placed into an aluminum pan containing sufficientacetone to completely cover the chip. After 60 seconds, the samples wereremoved from the acetone and assessed for any dissolution of thesurface, stickiness, or optical imperfections. The results are seen inTable F (see next page).

TABLE F Average Skin # of Thickness Passes Calc from By Optical SampleUnder Avg. % Avg % Microscopy Name UV Gel Gel (um) (um) Resistance toAcetone EXP 9 0 2.3 74 0 Poor, Skin turned white & cracked. EXP 9 2 2.166 8 Skin turned hazy and was slightly sticky EXP 9 6 5.8 184 42 Skinwas not sticky and remained clear EXP 9 10 4.7 152 76 Skin was notsticky and remained clear EXP 11 0 1.5 48 No skin Poor, Skin turnedwhite & formed cracked. EXP 11 2 2.1 67 Skin turned hazy and was stickyEXP 11 6 1.7 55 Skin turned hazy and was sticky EXP 11 10 2.0 64 Skinturned hazy and was sticky EXP 8 0 3.1 99 Poor, Skin turned white &cracked. EXP 8 2 2.8 90 Skin turned hazy EXP 8 6 3.6 115 Skin was notsticky and remained clear EXP 8 10 4.5 143 Skin was not sticky andremained clear EXP 10 0 4.0 128 No skin Poor, Skin turned white & formedcracked. EXP 10 2 1.3 42 Poor, Skin turned white & cracked. EXP 10 6 3.2104 Skin turned hazy and was sticky EXP 10 10 3.9 126 Skin turned hazyand was sticky EXP 10 15 2.8 91 Skin turned hazy and was sticky EXP 12 00.0 Poor, Skin turned white & cracked. EXP 12 2 0.7 23.0 3.5 Skin turnedhazy. EXP 12 10 3.5 113.6 31.0 Skin was mostly clear with haze in comeareas.

All the samples before UV exposure had severe surface attack under thistest. The surface became white and cracked. After UV exposure, thosecompositions that contained benzophenone formed crosslinked skins at adepth in accordance to the UV dose and benzophenone concentration. At 2to 35 microns depth (as measured optically) the articles had improvedchemical resistance over the unexposed samples without a crosslinkedskin. For the best chemical resistance, a cross-linked skin depth (asmeasured by optical microscopy) of greater than 35 microns waspreferred.

Next, a set of 3.2 mm Izod bars were made from the composition of EXP11. These bars were then exposed to UV-radiation from a 9 mm D bulb fromFusion UV systems, Inc., with and without the borosilicate glassdescribed in FIG. 7. The belt speed was set to 3 feet/min. A UV PowerPuck™ from EIT Instruments was first run through the UV oven to measurethe energy per pass or dose. The dose was measured as the energy from320-390 nm (UVA), 280-320 nm (UVB), 250-260 nm (UVC) and 395-445 nm(UVV). The dose was calculated in J/cm².

For the samples using the filtered glass (BS WG), the surfacetemperature was read before and after each pass. The borosilicate glasswas placed over the samples before they were passed through the UV oven.When the samples exited the oven, the glass was removed for thetemperature measurement. After the temperature was read, the glass wasplaced back over the samples and they were allowed to sit at 23° C.under the glass. After the sample sat for 30 minutes, the glass wasagain removed, the surface temperature was again measured, the glass wasreplaced and the sample was again sent through the chamber. This processwas continued for the desired number of passes.

The samples without the glass filter were run through the UV oven. Asthe samples exited the oven, they were immediately placed back on thebelt for the next pass. This process was continued until the desirednumber of passes were obtained.

One set of samples used the LEXAN sheet (1.6 mm thickness, neutralcolor, UV stabilized polycarbonate) as a filter.

The change in the Yellowness Index (delta YI) was determined bymeasuring the YI on a 1.6 mm bar after 48 hours at 23° C. in the darkafter the UV exposure. The results are shown in Table G.

TABLE G # of Delta Passes UVA + YI after UV Under UVA UVB UVC UVV UVB +Avg % 48 hrs Sample Filter UV (J/cm²) (J/cm²) (J/cm²) (J/cm²) UVC Gel ormore EXP 9 BS WG 0 0 0 0 0 0 2.2 0 EXP 9 BS WG 2 9.0 0.3 0.0 5.2 9 2.2 1EXP 9 BS WG 6 27.1 0.8 0.1 15.6 28 2.2 3 EXP 9 BS WG 10 45.2 1.3 0.226.0 47 5.9 4 EXP 9 none 0 0.0 0.0 0.0 0.0 0 2.3 0 EXP 9 none 2 10.7 3.10.4 4.9 14 2.1 2 EXP 9 none 6 32.7 9.7 1.1 15.1 44 5.8 7 EXP 9 none 1053.1 15.6 1.9 24.4 71 4.7 8 EXP 9 BS WG 10 52.0 1.8 0.2 28.9 54 4.1 EXP9 PC Sheet 10 1.5 0.5 0.1 17.7 2 2.5

Considering the BSWG samples, since the BSWG filter blocks the lowerwavelengths of light, the total UV energy of light (UV A, B, C) is lowerper pass than without the glass filter. But if one compares the samplesat similar Total UV energy (UVA+UVB+UVC=45+/−2 J/cm²), the samples underglass have a gel content of 5.9% (10 passes) vs 5.8% (6 passes) withoutthe filter. More importantly, even though the samples have the same gelcontent, the delta YI of the sample with the glass filter is only 3versus 7 for the sample with unfiltered light. Thus, for similar gelcontents, the change in YI (Yellowness Index) can be dramaticallyreduced.

Next a set of samples were run through the chamber without any delay for10 passes. One set of samples used the glass filter, and another usedthe LEXAN sheet. As seen in Table G, the sample with glass filtercontained ˜4.1% gel, whereas the sample with the LEXAN filter contained˜2.5% gel (which is similar to the gel content found on the twounexposed samples). The temperature of the samples can be controlled byvarious methods to control the crosslinking rate. The upper sampletemperature needs to be controlled to minimizing discoloration andwarping of the parts.

As seen from the data in Table G, the harmful UV radiation (UVB) can beblocked and still achieve crosslinking (5.9% gel at 47 J/cm² under glassvs 5.8% gel at 44 J/cm² of UVA+UVB+UVC). This is seen in FIG. 12. Thesample with the BSWG filter (diamond) was compared to the sample with nofilter (square). Samples receiving the same dosage had the same gelcontent, even though the wavelengths providing that energy differed.

In addition, the color of the samples exposed under BSWG glass havelower color shift. This is seen in FIG. 13. The sample with no filter(square) had a greater color shift compared to the samples with BSWGglass filter (triangle). The data also showed that while increasing thedose (# passes) increased the % insoluble cross-linked skin, it alsoincreased the color (Delta YI). For many applications, minimizing thecolor shift is critical. The data also shows that a desirable spectrumof UV light is predominately from 330 to 380 nm. Light greater than 380nm did not induce crosslinking.

For further verification regarding the preferred range of UV light forinducing crosslinking, 1.2 mm flame bars were prepared frompolycarbonate resin. UV long pass filters from Schott Glass AdvancedOptics Division were utilized with cut-on wavelengths at 280 (N-WG280),290 (N-WG290), 305 (N-WG305), and 320 (N-WG320) nm. These UV long passfilters block the light below these wavelengths and pass the light abovethem.

These UV filters were combined with spectral output from the 9 mm D bulbfrom Fusion UV systems, Inc. As shown in FIG. 14, spectral output poweris plotted versus wavelength of the UV-long pass filters. The data showsthat there is a significant amount of light—down to approximately 200nm—that can be blocked by the UV filters. The UV-long pass filters from280 to 320 nm will also show if these wavelengths are necessary ordetrimental to the UV crosslinking process.

The 1.2 mm flame bars were then passed though the UV chamber with D bulband with the UV-filters covering the samples. The samples were thenanalyzed for (1) color shift by measuring YI at 48 hours after UVexposure and (2) for cross-linked layer thickness by optical microscopyafter dissolving away the soluble portion. The results from the exposureof samples using the D bulb and long pass filters are indicated below inTables H-1 and H-2 (next page).

TABLE H-1 Long Pass UV Dosage Number Filter UVA UVB UVC UVV Passes (nm)(J/cm²) (J/cm²) (J/cm²) (J/cm²) 0 280 0 0 0 0 2 280 10.6 2.2 0 5.2 6 28031.9 6.7 0.1 15.5 10 280 53.2 11.1 0.1 25.8 15 280 79.8 16.7 0.1 38.7 20280 106.4 22.3 0.2 51.6 25 280 133 27.8 0.2 64.5 0 295 0 0 0 0 2 29512.2 1.9 0 5.9 6 295 36.5 5.8 0.1 17.6 10 295 60.8 9.6 0.1 29.4 15 29591.2 14.4 0.2 44.1 20 295 121.6 19.2 0.2 58.7 25 295 152 24 0.3 73.4 0305 0 0 0 0 2 305 12 1 0 5.8 6 305 36.1 2.9 0.1 17.5 10 305 60.2 4.9 0.129.2 15 305 90.2 7.3 0.1 43.8 20 305 120.3 9.7 0.2 57.4 25 305 150.412.1 0.2 73 0 320 0 0 0 0 2 320 11.8 0.2 0 5.9 6 320 35.3 0.7 0.1 17.610 320 58.9 1.2 0.1 29.3 15 320 88.4 1.8 0.2 44 20 320 117.8 2.4 0.258.7 25 320 147.3 3 0.3 73.4 0 None 0 0 0 0 2 None 12.2 3.7 0.5 5.9 6None 36.6 11.2 10.4 17.7 10 None 60.9 18.7 2.4 29.5 15 None 91.4 28 3.544.3 20 None 121.8 37.3 4.7 59 25 None 152.3 46.6 5.9 73.8

TABLE H-2 Long Pass Filter Delta Delta Gel Thickness Number Passes (nm)E* YI (microns) 0 280 0 0 0 2 280 0.7 1.2 0 6 280 1.5 2.5 25.4 10 2802.2 3.8 51.8 15 280 3.5 5.9 55.1 20 280 4.1 6.9 91.1 25 280 4.5 7.5 80.70 295 0 0 0 2 295 0.7 1.2 0 6 295 1.4 2.4 16.5 10 295 2.1 3.6 31.1 15295 3.3 5.7 58.5 20 295 3.9 6.7 95.1 25 295 4.3 7.4 101.7 0 305 0 0 0 2305 0.7 1.2 0 6 305 1.3 2.3 10.7 10 305 2 3.5 42.6 15 305 3.4 5.8 73.520 305 3.9 6.6 75.8 25 305 4.3 7.3 114.3 0 320 0 0 0 2 320 0.7 1.2 0 6320 1.2 2.1 6.2 10 320 1.8 3.2 32.8 15 320 3 5.2 42.4 20 320 3.5 6.1 9425 320 4 6.9 88.9 0 None 0 0 0 2 None 1.3 2.2 9.2 6 None 4.3 7.2 32 10None 5.9 9.9 55.3 15 None 7.6 12.5 92 20 None 8.1 13.3 115.7 25 None 8.213.5 120.2

With reference to FIG. 15, a plot of cross linked layer thickness(microns, optically obtained) versus the number of passes using the Dbulb show a slightly greater increase in cross link thickness per passwithout the filters in place.

With reference to FIG. 16, when comparing the cross-linked layerthickness versus the YI shift, the UV-filters show a dramatic decreasein the color shift—by approximately one-half—for a given cross-linkedlayer thickness. Accordingly, by selecting the appropriate wavelengthsof UV light, the desired amount of cross linked layer thickness can beachieved while dramatically decreasing the color shift. In an exemplaryembodiment, a process for enhancing the chemical resistance of a surfacemolded article includes a selecting an ultraviolet range from about 280nm to 360 nm.

Filter Tests

An XPC-1 polycarbonate formed from bisphenol-A and having 3.45 mole %4-hydroxybenzophenone endcaps and a molecular weight of 22,000 g/mol bypolycarbonate standards was cast into films of 20 micrometers (μm) to 40μm thickness.

A Fusion UV system was used to expose the films to UV radiation bypassing the films placed on a conveyor under a D-bulb to expose thefilm. Each pass provided approximately 6.0 J/cm² of UVA energy (320-390nm), 1.8 J/cm² of UVB energy (280-320 nm), 0.22 J/cm² of UVC energy(250-260 nm), and 2.9 J/cm² of UVV energy (395-445 nm) as measured by anEIT PowerPuck (EIT Inc., Sterling, Va.), when no filter was present.

Five films of the XPC-1 polymer were irradiated with filtered UV light.A long pass filter was used to remove specific wavelengths of light,with a cut-on wavelength of 200 nm or 320 nm. The films were irradiatedon either one surface or both surfaces for five passes, about 30 J/cm²of UVA on each surface. The films were about 0.2 mm (200 μm) thick. Theyellowness index (YI) was then measured at 10, 1000, 2500, and 30thousand minutes after exposure. This was done because it is known thatthe YI will increase sharply upon UV exposure, then reduce over time toa constant amount.

For reference, the performance of four different long pass filters isprovided in Table 17A. These filters have a different cut-on wavelength.The cut-on wavelength specifies the location of the transition from aregion of low transmission to an adjacent spectral region of hightransmission, defined here as the wavelength where the internaltransmission is 50%. This table indicates the percentage of incidentlight that remains when the filter is being used, as measured by an EITPowerPuck, with 100% indicating the incident light without the filter.

TABLE 17A Cut-on wavelength UVA UVB UVC UW (nm, T = 50%) (320-390 nm)(280-320 nm) (250-260 nm) (395-445 nm) 220 nm 100%  100%  100%  100% 280 nm 97% 60% 4% 99% 320 nm 87%  6% 4% 87% 395 nm 10%  0% 0% 87%

The results for the films of the XPC-1 polymer are shown in Table 17B.The UVA dosage is measured prior to passing through the long passfilter. Ex-01 is the control, with no exposure.

TABLE 17B Ex-01 Ex-02 Ex-03 Ex-04 Ex-05 Component XPC-1 XPC-1 XPC-1XPC-1 XPC-1 Dose (J/cm², UVA) 0 30 30 30 30 Wavelength cut-on (nm) N/A200 320 200 320 Sides irradiated 0 1 1 2 2 Gel thickness (μm) 0 40 13160 160 YI (0 min) 0.77 12.50 5.80 13.56 17.70 YI (1000 min) 0.77 10.033.47 13.37 13.89 YI (2500 min) 0.77 9.30 3.26 13.26 12.87 YI (30000 min)0.77 7.84 2.70 12.81 9.14

As can be seen here, using a cut-on wavelength of 320 nm sharply reducedthe YI compared to the cut-on of 200 nm. The change in YI was less than9.0 for exposure on both surfaces when a cut-on of 320 nm was used aswell. The YI values at 2500 minutes and 30000 minutes best illustratethe benefits of the filters and the treatment of the articles duringnormal handling. It is noted that the YI value at 10 minutes can bedistorted by many variables.

Chemical Resistance Tests

A set of chemical resistance tests was performed. The tests wereperformed using an XPC-2 polymer, which was formed from bisphenol-A andhad 5.5 mole % 4-hydroxybenzophenone endcaps and a molecular weight of17,000 g/mol by polycarbonate standards. 50 parts by weight of the XPC-2polymer was blended with 50 parts by weight of HF-PC, 0.08 phr KSS, 0.06phr phosphite stabilizer to form a composition (CR1). Parts having athickness of 2.5 millimeters (mm) were made from the composition, andexposed to various dosages (0, 12, 36, 60 J/cm² of UVA, measured beforefiltering) while covered with long pass filters of different cut-onwavelengths (220, 280, 320, 395 nm). The YI was then measured after 10minutes, 24 hours, 48 hours, and 168 hours at 23° C. YI was measuredfollowing ASTM E313-73 (D1925). The color difference dE* was thencalculated. The haze was also measured before and after acetoneimmersion. The part was immersed for 60 seconds in acetone, then driedin air for 1 minute, soaked in deionized water for 5 minutes, dried, andplaced in the dark before measurement. EX-10 is the control (noexposure). The results are shown in Tables 18A and 18B.

TABLE 18A Ex-10 Ex-11 Ex-12 Ex-13 Ex-14 Ex-15 Ex-16 Component CR1 CR1CR1 CR1 CR1 CR1 CR1 Dose (UVA, J/cm²) 0 12 36 60 12 36 60 Cut-onwavelength (nm) N/A 220 220 220 280 280 280 YI (23° C., 10 min) 2.0 9.020.7 25.1 8.0 19.6 22.5 YI (23° C., 24 hr) 2.0 6.4 14.5 17.8 5.2 12.314.6 YI (23° C., 48 hr) 1.9 6.1 13.3 16.2 5.0 11.3 13.7 YI (23° C., 168hr) 2.1 5.6 11.8 13.9 4.9 9.4 12.0 dE* (168 hr) — 2.1 5.6 6.0 1.5 4.15.6 Gel Thickness (microns) 0 0 0 28 0 0 4.3 Haze, Before immersion 6.64.6 6.9 6.7 6.8 6.9 6.8 Haze, Acetone Immersion 80.1 49.9 45.9 23.8 37.27.3 7.8

TABLE 18B Ex-17 Ex-18 Ex-19 Ex-20 Ex-21 Ex-22 Component CR1 CR1 CR1 CR1CR1 CR1 Dose (UVA, J/cm²) 12 36 60 12 36 60 Cut-on wavelength (nm) 320320 320 395 395 395 YI (23° C., 10 min) 10.6 21.1 22.9 2.0 2.1 2.1 YI(23° C., 24 hr) 7.6 12.3 14.7 1.9 2.0 2.1 YI (23° C., 48 hr) 6.1 12.013.6 1.9 2.0 2.0 YI (23° C., 168 hr) 5.7 9.1 11.5 2.1 2.2 2.2 dE* (168hr) 2.1 3.9 5.3 0.0 0.1 0.1 Gel Thickness (microns) 0 0 0 0 0 0 Haze,Before immersion 6.6 7.7 7.2 7.4 7.2 7.0 Haze, Acetone Immersion 13.023.2 6.5 92.1 86.9 91.7

Comparing the examples with the same dosage, the filter with a cut-onwavelength of 395 nm was most effective in reducing the overall YI andthe color difference, but was not effective at inducing crosslinking, asindicated by the high haze values. The hydroxybenzophenone unit absorbslight at about 335 nm, while the carbonate units absorb light at about245 nm. Using the 395 nm filter, the hydroxybenzophenone absorbancewavelength was blocked, so very little crosslinking could occur. Usingthe 220 nm filter, both units are absorbing light, and while there is asignificant gel (Ex-13), there is also significant haze, which isbelieved to be due to degradation from Fries rearrangement. A filterwith a cut-on wavelength of 280 nm or 320 nm provided the best balanceof color (i.e. low YI or dE*) and high acetone resistance (i.e. lowhaze).

Next, a flame performance test was performed with the XPC-1 polymer(polycarbonate formed from bisphenol-A, 3.45 mole %4-hydroxybenzophenone endcaps, a molecular weight of 22,000 g/mol).913-1 was the control. Measurements were taken before and after UVexposure. The samples received a total of 30 J/cm² on each side using aFusion UV system. The results are shown in Table 19.

TABLE 19 Components 913-1 913-2 XPC-1 (3.45 mol %) (pbw) 50 LF-PC (pbw)100 50 Rimar Salt (phr) 0.1 0.1 Phosphite stabilizer (phr) 0.06 0.06 MFR(1.2 kg/300 C., 360 s) 6.67 9.28 MFR (1.2 kg/300 C., 1080 s) 7.17 9.26Gel Thickness (micron) 0 9.85 Delta YI 3.4 15.4 Flame Performance(non-UV exposure) p(FTP) for V0 @ 1.5 mm (48 hr) 0 0 flaming drips 2/33/3 p(FTP) for V0 @ 1.2 mm (48 hr) 0 0 flaming drips 2/3 2/3 p(FTP) forV0 @ 1.0 mm (48 hr) 0 0 flaming drips 3/3 3/3 5VA @ 1.5 mm (48 hr) FailFail Flame Performance (after UV exposure) p(FTP) for V0 @ 1.5 mm (48hr) 0 0.983 flaming drips  6/10  0/18 p(FTP) for V0 @ 1.2 mm (48 hr) 00.2 flaming drips  8/10  1/18 p(FTP) for V0 @ 1.0 mm (48 hr) 0.74 0.57flaming drips  1/18  1/18 5VA @ 1.5 mm Fail Pass Chemical Resistance(Elongation @ Break) As molded bar 134.2 138.0 Acetone @ 0.5% strain NoUV 10.5 8.9 Exposed to UV 5.9 78.9 Acetone @ 1% strain No UV 0.0 0.0Exposed to UV 0.0 68.0As seen here, prior to UV exposure, the blend containing XPC (913-2) didnot attain a V0 or 5VA rating. However, after UV exposure, the XPC blendpasses the 5VA and V0 rating at 1.5 mm thickness. The chemicalresistance is also higher after UV exposure, and higher compared to thenon-XPC control.

Lame Scale Study

A large scale study was performed using 13 different batches. Thebatches used one of three cross-linkable polycarbonate resins. XPC-A wasa bisphenol-A polymer with 3.79 wt % 4-hydroxybenzophenone (HBP) endcapsand a target weight average molecular weight (Mw) of 17,000. Whenmeasured with a UV detector, XPC-A had an Mw of 16,692 and a PDI of 3.3.When measured with an RI detector, XPC-A had an Mw of 23,123 and a PDIof 2.4. XPC-B was a bisphenol-A polymer with 3.05 wt % HBP endcaps and atarget Mw of 22,000. When measured with a UV detector, XPC-B had an Mwof 20,600 and a PDI of 3.4. When measured with an RI detector, XPC-B hadan Mw of 26,443 and a PDI of 2.4. XPC-C was a bisphenol-A polymer with2.58 wt % HBP endcaps and a target Mw of 26,000. When measured with a UVdetector, XPC-C had an Mw of 24,455 and a PDI of 3.7. When measured withan RI detector, XPC-C had an Mw of 32,432 and a PDI of 2.7.

Some of the batches included LF-PC, which is a bisphenol-A homopolymerprepared by the interfacial process having an Mw of about 30,000Daltons. The batches also included Rimar salt (flame retardant) and aphosphite stabilizer (Irgaphos 168). The formulation of the 13 batchesis shown in Table 20A and Table 20B.

TABLE 20A Name B-1 B-2 B-3 B-4 B-5 B-6 B-7 B-8 B-9 XPC-A (wt %) 99.8487.36 74.88 49.92 XPC-B (wt %) 99.84 87.36 74.88 62.40 49.92 LF-PC (wt%) 12.48 24.96 49.92 12.48 24.96 37.44 49.92 Rimar Salt (wt %) 0.10 0.100.10 0.10 0.10 0.10 0.10 0.10 0.10 Phosphite (wt %) 0.06 0.06 0.06 0.060.06 0.06 0.06 0.06 0.06

TABLE 20B Name B-10 B-11 B-12 B-13 XPC-C (wt %) 99.84 74.88 62.40 49.92LF-PC (wt %) 24.96 37.44 49.92 Rimar Salt (wt %) 0.10 0.10 0.10 0.10Phosphite (wt %) 0.06 0.06 0.06 0.06

The 13 batches were used to make 50 samples which were then exposed tovarious doses of UV light. The samples were exposed to either filteredlight or unfiltered light. The unfiltered light was provided by a FusionUV system, which used a D-bulb electrodeless bulb. The filtered lightwas provided by a Loctite Zeta 7411-S system, which used a 400 W D-bulbmetal halide arc lamp and behaved like a filter with a 280-nm cut-onwavelength. The samples were exposed on both sides beneath the UV lightsfor the equivalent UVA dosage of 12, 36, or 60 J/cm² per side. The UVenergy for each system is provided below in Table 21A and Table 21B, andwas measured using an EIT PowerPuck. In the results section, the UVsource is listed as either U for unfiltered light, or F for filteredlight, and the UVA dosage is listed.

TABLE 21A Loctite (filtered light). Loctite Dose UVA UVB UVC UVVFiltered J/cm² J/cm² J/cm² J/cm²  2 passes 12.0 2.4 0 7.3  6 passes 36.07.2 0 21.9 10 passes 60.2 12.1 0 36.6

TABLE 21B Fusion (unfiltered light) Fusion UV UVA UVB UVC UVV UnfilteredJ/cm² J/cm² J/cm² J/cm²  2 passes 12.0 3.7 0.45 5.8  6 passes 35.9 11.01.34 17.5 10 passes 59.9 18.3 2.24 29.2

The flame performance of the 50 samples was tested using the methodsdescribed above near Tables 5 and 6. The pFTP values for these sampleswere based on 18 bars. The bars were conditioned for either 2 days or 7days, then tested. The pFTP was calculated separately for the 2-daysamples and the 7-day samples. The pFTP for V0 performance and V1performance was calculated. It should be noted that the pFTP(V1) for anygiven sample is expected to be higher than the pFTP(V0) for the sample,because the V1 test is less stringent than the V0 test. The fraction ofdrips is also reported.

Chemical resistance was measured by the elongation at break of tensilebars having 3.2 mm thickness. For chemically exposed samples, thetensile bars were put under 1% strain at 23° C. and exposed to acetone.They were then removed from the strain jigs and the tensile elongationat break was measured following the ASTM D638 Type I method at 50mm/min. The tensile elongation at break was measured under fourdifferent conditions: before UV exposure and before exposure to acetone(“No UV, No Chem”); before UV exposure and after exposure to acetone(“No UV, Ace”); after UV exposure and before exposure to acetone (“UV,No Chem”); and after UV exposure and after exposure to acetone (“UV,Ace”). Units were in percentage. The percentage of retention of tensileelongation (% retention) was the “UV, Ace” divided by the “UV, No Chem”.Acetone was applied to six bars, while the “No Chem” control data wasobtained with only 3 bars.

The degree of crosslinking was quantified by dissolving thenon-cross-linked fraction of the plaque in methylene chloride andisolating the insoluble gel layer. The thickness of the insoluble gellayer was measured using optical microscopy, and is reported in microns.

The molecular weight of the samples was measured before and after UVexposure using a UV detector. The percentage change in the molecularweight was calculated as the change divided by the molecular weightbefore UV exposure.

The Yellowness Index (YI) was measured on 3.2 mm tensile bars before UVexposure and at least 48 hours after UV exposure using an X-Rite Colori7 benchtop spectrophotometer in the transmission mode using CIELABcolor equation, an observer angle of 2 degrees, and illuminant C as thelight source. YI was measured following ASTM E313-73 (D1925). The lighttransmission (% T) was measured concurrently with the YI on the samebar.

The MFR for each sample was calculated using the ASTM D1238 method, 1.2kg load, 300° C. temperature, 360 second dwell.

The glass transition temperature (Tg) was measured after UV exposure.The temperature of the bars after UV exposure was also taken using aCole Palmer IR Thermometer (model 08406-16), and is reported in degreesFahrenheit (° F.). The bars for flame testing and tensile testing wereseparately measured, and are listed in separate columns.

The results of the 50 samples are reported in Tables 22A-22H.

TABLE 22A Dose fraction of Batch # Dose UV p(FTP) @ V0 p(FTP) @ V1 dripsSample # passes J/cm² source 2 day 7 day 2 day 7 day 2 day 7 day 1 B-102 12 F 0.1606 0.1094 0.2373 0.9898 0.22 0.00 2 B-4 2 12 F 0.0002 0.00010.0007 0.0001 0.56 0.60 3 B-5 2 12 U 0.0495 0.4777 0.7199 1.0000 0.060.00 4 B-13 2 12 F 0.0552 0.0994 0.0776 0.1426 0.33 0.28 5 B-7 10 60 U0.2199 0.8826 0.9944 1.0000 0.00 0.00 6 B-10 10 60 F 0.0089 0.60190.3666 0.9999 0.17 0.00 7 B-11 2 12 U 0.0017 0.0021 0.3334 0.6822 0.170.06 8 B-4 10 60 U 0.0009 0.0001 0.0366 0.1409 0.39 0.28 9 B-11 6 36 U0.0029 0.0633 0.2317 1.0000 0.22 0.00 10 B-9 6 36 U 0.0014 0.0019 0.26790.7170 0.17 0.06 11 B-10 6 36 U 0.0002 0.0002 0.0040 0.9999 0.50 0.00 12B-13 6 36 F 0.0400 0.0053 0.3628 0.7460 0.17 0.00 13 B-5 10 60 U 00.0003 0 0.9889 0.55 0.00 14 B-3 2 12 F 0 0 0 0 1.00 1.00 15 B-5 6 36 F0 0 0 0.7444 0.90 0.06 16 B-10 2 12 F 0.0030 0 0.2370 0.0040 0.22 0.5017 B-10 2 12 U 0.0048 0.0001 0.7403 0.7228 0.05 0.06 18 B-11 10 60 F0.0019 0.0046 0.2373 0.9510 0.22 0.00 19 B-3 10 60 F 0.1040 0.13560.3625 0.9967 0.17 0.00 20 B-11 10 60 U 0.4147 0.7624 0.9999 1.0000 0.000.00 21 B-3 6 36 F 0.4363 0.0324 0.7435 0.9572 0.06 0.00 22 B-4 2 12 U0.6923 0.0001 0.7451 0.0001 0.06 0.60 23 B-6 10 60 F 0.4526 0.06940.7367 0.9694 0.06 0.00 24 B-8 2 12 U 0.0061 0.0089 0.0364 0.2346 0.390.22 25 B-4 10 60 U 0.2224 0.0421 0.5317 0.9872 0.11 0.00

TABLE 22B Dose fraction of Batch # Dose UV p(FTP) @ V0 p(FTP) @ V1 dripsSample # passes J/cm² source 2 day 7 day 2 day 7 day 2 day 7 day 26 B-76 36 U 0.1683 0.382 0.5337 0.9999 0.11 0.00 27 B-12 6 36 F 0.1529 0.30920.3666 0.9943 0.17 0.00 28 B-9 2 12 F 0.0079 0 0.0144 0.0001 0.44 0.6029 B-9 10 60 F 0.5996 0.6319 0.9975 0.9998 0.00 0.00 30 B-10 2 12 F0.5211 0.0057 0.7450 0.4921 0.06 0.11 31 B-11 2 12 F 0.2636 0.06010.5348 0.1426 0.11 0.28 32 B-10 10 60 U 0.3347 0.8172 0.7446 1.0000 0.060.00 33 B-2 6 36 U 0.3207 0.0606 0.7247 0.9810 0.06 0.00 34 B-4 6 36 F0.1718 0.097 0.3654 0.7439 0.17 0.06 35 B-1 10 60 F 0.0343 0.0135 0.11060.9983 0.30 0.00 36 B-7 2 12 F 0 0.0028 0 0.0144 0.70 0.44 37 B-8 6 36 F0.3153 0.0776 0.9987 0.9902 0.00 0.00 38 B-3 2 12 U 0.0974 0 0.2360 00.22 1.00 39 B-1 10 60 U 0.0974 0 0.3428 0.2366 0.17 0.22 40 B-13 6 36 U0.0900 0.0017 0.9953 0.9919 0.00 0.00 41 B-4 10 60 F 0 0.0141 0 0.51120.60 0.11 42 B-13 2 12 U 0.0001 0 0.0034 0.0039 0.50 0.50 43 B-1 2 12 F0 0 0 0 1.00 1.00 44 B-4 2 12 U 0 0 0 0 1.00 0.80 45 B-13 10 60 F 0.11510.0229 0.7335 0.9819 0.06 0.00 46 B-1 10 60 F 0 0 0 0.0035 0.70 0.50 47B-13 2 12 U 0.3119 0 0.7237 0.0141 0.06 0.44 48 B-1 2 12 U 0.0012 0.00040.0041 0.0346 0.50 0.39 49 B-3 10 60 U 0.0032 0.0003 0.0142 0.9943 0.440.00 50 B-13 10 60 U 0.0799 0.4694 0.7398 0.9979 0.06 0.00

TABLE 22C Chemical resistance (6 bars @ 1% strain) Elongation at BreakGel layer No UV, No UV, UV, No UV, % ret thickness Sample No Chem AceChem Ace (UV, Ace) (microns) 1 128.73 0 124.88 93.75 75.07 0.0 2 108.230 101.25 6.72 6.63 0.0 3 137.98 0 116.75 27.38 23.45 9.0 4 136.67 2.98123.83 47.52 38.37 0.0 5 136.99 0 110.25 98.57 89.41 30.9 6 128.73 0115.38 86.80 75.23 22.9 7 133.18 0 131.55 95.18 72.35 3.1 8 93.24 076.85 79.92 103.99 14.7 9 133.18 0 118.45 107.72 90.94 21.3 10 130.88 0125.3 95.47 76.19 7.7 11 128.73 0 113.35 88.43 78.02 29.2 12 136.67 2.98127.83 76.28 59.67 0.0 13 137.98 0 106 103.13 97.29 32.9 14 129.81 0 1273.13 2.47 0.0 15 137.98 0 117.3 108.18 92.23 11.1 16 128.73 0 124.8876.23 61.05 0.0 17 128.73 0 117.68 82.90 70.45 8.8 18 133.18 0 121.48108.38 89.22 10.2 19 129.81 0 112.23 103.27 92.02 13.4 20 133.18 0107.73 95.65 88.79 34.4 21 129.81 0 100.1 45.43 45.38 7.9 22 93.24 081.03 8.13 10.04 2.3 23 125.58 0 108.9 108.48 99.61 18.8 24 136.23 0133.35 27.32 20.48 2.3 25 108.23 0 105.25 69.35 65.89 20.0

TABLE 22D Chemical resistance (6 bars @ 1% strain) Elongation at BreakGel layer No UV, No UV, UV, No UV, % ret thickness Sample No Chem AceChem Ace (UV, Ace) (microns) 26 136.99 0 110.48 108.82 98.50 19.5 27129.23 0 121.98 67.77 55.56 0.0 28 130.88 0 135.1 6.75 5.00 0.0 29130.88 0 116.58 69.25 59.40 0.0 30 128.73 0 127.35 54.02 42.42 0.0 31133.18 0 129.13 42.80 33.14 0.0 32 128.73 0 109.23 102.18 93.55 51.8 33134.78 0 110.35 96.02 87.01 21.0 34 93.24 0 96.35 16.72 17.35 0.0 35116.33 0 113.78 106.75 93.82 18.8 36 136.99 0 120.23 12.87 10.70 0.0 37136.23 0 122.7 83.15 67.77 5.7 38 129.81 0 120.73 4.75 3.93 5.5 39116.33 0 102.65 72.43 70.56 29.5 40 136.67 2.98 125.1 107.92 86.27 8.541 108.23 0 109.43 48.08 43.94 5.7 42 136.67 2.98 127.2 109.03 85.72 0.043 116.33 0 118.58 0.00 0.00 0.0 44 108.23 0 102.43 5.29 5.16 0.0 45136.67 2.98 120.23 103.83 86.36 0.0 46 116.33 0 102.48 84.37 82.33 21.447 136.67 2.98 126.43 82.95 65.61 0.0 48 116.33 0 104.6 6.27 5.99 5.9 49129.81 0 110.63 98.00 88.58 25.0 50 136.67 2.98 120.83 107.20 88.72 5.1

TABLE 22E Molecular Weight % YI Before After Change Before After SampleUV UV Delta Mw UV UV Delta 1 24455 27640 3185 13% 3.34 5.7 2.4 2 2113422481 1347  6% 2.17 5.42 3.3 3 20600 25253 4653 23% 2.83 7.92 5.1 425454 31531 6077 24% 2.27 5.54 3.3 5 21716 31552 9836 45% 2.26 23.6421.4 6 24455 32396 7941 32% 3.34 12.1 8.8 7 24920 30657 5737 23% 2.37.63 5.3 8 21134 29369 8235 39% 2.17 22.44 20.3 9 24920 34404 9484 38%2.3 22 19.7 10 22725 32682 9957 44% 2.3 20.31 18.0 11 24455 32369 791432% 3.34 26.25 22.9 12 25454 33282 7828 31% 2.27 10.15 7.9 13 2060028627 8027 39% 2.83 27.78 25.0 14 18982 21019 2037 11% 2.11 6.09 4.0 1520600 26287 5687 28% 2.83 10.87 8.0 16 24455 27917 3462 14% 3.34 6.783.4 17 24455 30038 5583 23% 3.34 8.96 5.6 18 24920 33477 8557 34% 2.311.22 8.9 19 18982 23510 4528 24% 2.11 9.42 7.3 20 24920 36659 11739 47%2.3 25.7 23.4 21 18982 23455 4473 24% 2.11 9.01 6.9 22 21134 24797 366317% 2.17 7.97 5.8 23 21829 27440 5611 26% 2.38 9.88 7.5 24 22460 273064846 22% 2.04 7.3 5.3 25 21134 29505 8371 40% 2.17 22.44 20.3

TABLE 22F Molecular Weight % YI Before After Change Before After SampleUV UV Delta Mw UV UV Delta 26 21716 29435 7719 36% 2.26 20.95 18.7 2724213 34088 9875 41% 2.31 8.48 6.2 28 22725 26028 3303 15% 2.3 5.43 3.129 22725 32122 9397 41% 2.3 11.68 9.4 30 24455 27879 3424 14% 3.34 6.282.9 31 24920 28359 3439 14% 2.3 5.4 3.1 32 24455 33815 9360 38% 3.3430.06 26.7 33 17925 23247 5322 30% 1.98 24.23 22.3 34 21134 26620 548626% 2.17 9.75 7.6 35 16692 21618 4926 30% 2.8 14.66 11.9 36 21716 248433127 14% 2.26 5.33 3.1 37 22460 30207 7747 34% 2.04 9.81 7.8 38 1898222384 3402 18% 2.11 8.32 6.2 39 16692 22750 6058 36% 2.8 34.42 31.6 4025454 36135 10681 42% 2.27 18.51 16.2 41 21134 28420 7286 34% 2.17 12.910.7 42 25454 29740 4286 17% 2.27 7.92 5.7 43 16692 19291 2599 16% 2.86.38 3.6 44 21134 24302 3168 15% 2.17 8.25 6.1 45 25454 36279 10825 43%2.27 10.95 8.7 46 16692 21576 4884 29% 2.8 14.2 11.4 47 25454 30551 509720% 2.27 7.96 5.7 48 16692 19817 3125 19% 2.8 10.39 7.6 49 18982 251496167 32% 2.11 25.68 23.6 50 25454 36762 11308 44% 2.27 18.32 16.1

TABLE 22G % T Before After XPC MFR Tg Temperature ° F. Sample UV UVDelta wt % g/10 min ° C. Flame Tensile 1 88.296 86.828 −1.5 2.58 5.18157 166 168 2 88.901 87.085 −1.8 1.99 11.7 155 172 177 3 88.349 85.826−2.5 3.05 9.14 154 181 183 4 88.779 87.258 −1.5 1.26 5.99 157 168 167 588.485 79.886 −8.6 2.34 8.32 160 204 208 6 88.296 84.304 −4.0 2.58 5.18161 190 200 7 89.095 86.308 −2.8 1.92 5.04 156 180 183 8 88.901 79.264−9.6 1.99 11.7 158 203 205 9 89.095 80.411 −8.7 1.92 5.04 158 195 195 1088.776 80.983 −7.8 1.55 7.46 157 193 197 11 88.296 77.975 −10.3 2.585.18 159 194 191 12 88.779 85.469 −3.3 1.26 5.99 157 188 182 13 88.34977.5 −10.8 3.05 9.14 161 206 205 14 89.255 86.945 −2.3 2.83 14.5 154 184175 15 88.349 84.481 −3.9 3.05 9.14 158 183 187 16 88.296 86.436 −1.92.58 5.18 157 171 184 17 88.296 85.519 −2.8 2.58 5.18 157 182 184 1889.095 84.947 −4.1 1.92 5.04 158 193 199 19 89.255 85.715 −3.5 2.83 14.5158 185 194 20 89.095 79.14 −10.0 1.92 5.04 159 200 203 21 89.255 86.036−3.2 2.83 14.5 156 193 185 22 88.901 86.199 −2.7 1.99 11.7 155 178 18423 88.826 85.491 −3.3 2.69 8.95 159 191 183 24 88.787 86.437 −2.4 1.928.3 156 182 176 25 88.901 80.338 −8.6 1.99 11.7 158 201 205

TABLE 22H % T Before After XPC MFR Tg Temperature ° F. Sample UV UVDelta wt % g/10 min ° C. Flame Tensile 26 88.485 80.336 −8.1 2.34 8.32158 198 198 27 89.215 86.388 −2.8 1.6 5.68 157 192 182 28 88.776 87.176−1.6 1.55 7.46 155 190 177 29 88.776 84.811 −4.0 1.55 7.46 157 196 20530 88.296 86.863 −1.4 2.58 5.18 156 184 184 31 89.095 87.338 −1.8 1.925.04 156 178 178 32 88.296 76.164 −12.1 2.58 5.18 161 201 205 33 89.02579.099 −9.9 3.33 18.5 159 197 200 34 88.901 85.327 −3.6 1.99 11.7 156185 194 35 88.378 82.83 −5.5 3.79 19.9 159 194 201 36 88.485 87.029 −1.52.34 8.32 154 174 192 37 88.787 85.054 −3.7 1.92 8.3 157 190 190 3889.255 85.909 −3.3 2.83 14.5 154 190 186 39 88.378 75.455 −12.9 3.7919.9 163 205 209 40 88.779 81.852 −6.9 1.26 5.99 158 198 199 41 88.90184.049 −4.9 1.99 11.7 154 190 192 42 88.779 86.12 −2.7 1.26 5.99 156 184186 43 88.378 86.569 −1.8 3.79 19.9 150 179 181 44 88.901 86.06 −2.81.99 11.7 154 170 178 45 88.779 85.061 −3.7 1.26 5.99 154 182 185 4688.378 83.193 −5.2 3.79 19.9 155 182 188 47 88.779 86.296 −2.5 1.26 5.99156 170 180 48 88.378 84.994 −3.4 3.79 19.9 153 173 185 49 89.255 78.57−10.7 2.83 14.5 160 205 199 50 88.779 81.826 −7.0 1.26 5.99 158 208 201

Looking at Tables 22A-22B, one surprising finding was that the 7-daypFTP for many samples was higher than the 2-day pFTP. This behavior wasexactly the opposite of the expected behavior. Looking at Tables22E-22F, the YI was much lower when filtered light was used instead ofunfiltered light, particularly at the high dosages.

Many of the batches were compositions that had a cross-linkablepolycarbonate resin having endcaps derived from 4-hydroxybenzophenoneand a weight average molecular weight (Mw) from 15,000 to 30,000 and aPDI from 3.0 to 4.0 as measured by GPC using a UV detector andpolycarbonate standards; contained at least 45 wt % of the polycarbonatecross-linkable polycarbonate resin; had a 4-hydroxybenzophenone contentbetween 1.2 wt % and 4 wt %; had a melt flow rate (MFR) of 7 to 20 g/10min; and had a % T of 85% or greater at 3.2 mm thickness prior to UVexposure.

Some of the batch compositions had a cross-linkable polycarbonate resinhaving endcaps derived from 4-hydroxybenzophenone and a weight averagemolecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 asmeasured by GPC using a UV detector and polycarbonate standards;contained at least 45 wt % of the polycarbonate cross-linkablepolycarbonate resin; had a 4-hydroxybenzophenone content between 1.2 wt% and 4 wt %; had a melt flow rate (MFR) of 7 to 20 g/10 min; had a % Tof 85% or greater at 3.2 mm thickness prior to UV exposure; had a % T of75% or greater at 3.2 mm thickness after UV exposure; and had a gellayer of at least 8 microns thickness after UV exposure. In addition tothese properties, a few compositions also had a pFTP(V1) of at least0.95 at 1.2 mm thickness after aging for 7 days at 70° C.; a delta YIvalue of 12 or less at 3.2 mm thickness measured at least 48 hours afterUV exposure; a pFTP(V0) of at least 0.6 at 1.2 mm thickness; a %retention of 85% or greater at 3.2 mm thickness in a tensile elongationat break test using the ASTM D638 Type I method at 50 mm/min afterexposure to acetone under 1% strain at 23° C.; and/or a % retention of90% or greater at 3.2 mm thickness in a tensile elongation at break testusing the ASTM D638 Type I method at 50 mm/min after exposure to acetoneunder 1% strain at 23° C.

Other batch compositions had a cross-linkable polycarbonate resin havingendcaps derived from 4-hydroxybenzophenone and a weight averagemolecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 asmeasured by GPC using a UV detector and polycarbonate standards;contained at least 45 wt % of the polycarbonate cross-linkablepolycarbonate resin; had a 4-hydroxybenzophenone content between 1.2 wt% and 4 wt %; had a melt flow rate (MFR) of 7 to 20 g/10 min; had a % Tof 85% or greater at 3.2 mm thickness prior to UV exposure; had a % T of75% or greater at 3.2 mm thickness after UV exposure; and after UVexposure had an increase in Mw of at least 30% as measured by GPC usinga UV detector and polycarbonate standards. In addition to theseproperties, a few compositions also had a pFTP(V1) of at least 0.95 at1.2 mm thickness after aging for 7 days at 70° C.; a delta YI value of12 or less at 3.2 mm thickness measured at least 48 hours after UVexposure; a pFTP(V0) of at least 0.6 at 1.2 mm thickness; a % retentionof 85% or greater at 3.2 mm thickness in a tensile elongation at breaktest using the ASTM D638 Type I method at 50 mm/min after exposure toacetone under 1% strain at 23° C.; and/or a % retention of 90% orgreater at 3.2 mm thickness in a tensile elongation at break test usingthe ASTM D638 Type I method at 50 mm/min after exposure to acetone under1% strain at 23° C.

Some of the batch compositions had a cross-linkable polycarbonate resinhaving endcaps derived from 4-hydroxybenzophenone and a weight averagemolecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 asmeasured by GPC using a UV detector and polycarbonate standards;contained at least 45 wt % of the polycarbonate cross-linkablepolycarbonate resin; had a 4-hydroxybenzophenone content between 1.2 wt% and 4 wt %; had a melt flow rate (MFR) of 7 to 20 g/10 min; had a % Tof 85% or greater at 3.2 mm thickness prior to UV exposure; had a % T of75% or greater at 3.2 mm thickness after UV exposure; either (i) a gellayer of at least 8 microns thickness after UV exposure or (ii) anincrease in Mw of at least 30% as measured by GPC using a UV detectorand polycarbonate standards; and a % retention of 85% or greater at 3.2mm thickness in a tensile elongation at break test using the ASTM D638Type I method at 50 mm/min after exposure to acetone under 1% strain at23° C. In addition to these properties, a few compositions also had apFTP(V1) of at least 0.95 at 1.2 mm thickness after aging for 7 days at70° C.; a delta YI value of 12 or less at 3.2 mm thickness measured atleast 48 hours after UV exposure; and/or a pFTP(V0) of at least 0.6 at1.2 mm thickness.

Some of the batch compositions had a cross-linkable polycarbonate resinhaving endcaps derived from 4-hydroxybenzophenone and a weight averagemolecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 asmeasured by GPC using a UV detector and polycarbonate standards;contained at least 45 wt % of the polycarbonate cross-linkablepolycarbonate resin; had a 4-hydroxybenzophenone content between 1.2 wt% and 4 wt %; had a melt flow rate (MFR) of 7 to 20 g/10 min; had a % Tof 85% or greater at 3.2 mm thickness prior to UV exposure; had a % T of75% or greater at 3.2 mm thickness after UV exposure; either (i) a gellayer of at least 8 microns thickness after UV exposure or (ii) anincrease in Mw of at least 30% as measured by GPC using a UV detectorand polycarbonate standards; and a % retention of 90% or greater at 3.2mm thickness in a tensile elongation at break test using the ASTM D638Type I method at 50 mm/min after exposure to acetone under 1% strain at23° C. In addition to these properties, a few compositions also had apFTP(V1) of at least 0.95 at 1.2 mm thickness after aging for 7 days at70° C.; a delta YI value of 12 or less at 3.2 mm thickness measured atleast 48 hours after UV exposure; and/or a pFTP(V0) of at least 0.6 at1.2 mm thickness.

Additional batch compositions had a cross-linkable polycarbonate resinhaving endcaps derived from 4-hydroxybenzophenone, a weight averagemolecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 asmeasured by GPC using a UV detector and polycarbonate standards, and a4-hydroxybenzophenone content from 3.0 to 4.5 wt % in the cross-linkableresin; an overall 4-hydroxybenzophenone content in the composition ofbetween 1.2 wt % and 4 wt %; and a melt flow rate (MFR) of 7 to 20 g/10min measured at 300° C./1.2 kg/360 sec dwell; and could form articlesthat after UV exposure had a gel layer of at least 5 microns thicknessand had a pFTP(V1) of at least 0.95 at 1.2 mm thickness after aging for7 days at 70° C.

Still other batch compositions had a cross-linkable polycarbonate resinhaving endcaps derived from 4-hydroxybenzophenone, a weight averagemolecular weight (Mw) from 15,000 to 30,000 and a PDI from 3.0 to 4.0 asmeasured by GPC using a UV detector and polycarbonate standards, and a4-hydroxybenzophenone content from 3.0 to 4.5 wt % in the polycarbonateresin; a melt flow rate (MFR) of 7 g/10 min or higher, measured at 300°C./1.2 kg/360 sec dwell; and could be used to form injection moldedarticles having a YI of 15 or less at 3.2 mm thickness and having a %retention of 85% or greater at 3.2 mm thickness in a tensile elongationat break test using the ASTM D638 Type I method at 50 mm/min afterexposure to acetone under 1.0% strain at 23° C. In addition to theseproperties, some of the articles formed from the compositions also had apFTP(V1) of at least 0.70 at 1.2 mm thickness after aging for 7 days at70° C.; and/or a YI of 8 or less; or the composition had a melt flowrate (MFR) of 7 to 15 g/10 min. Many of the compositions included aflame retardant, and the injection molded article had a pFTP(V1) of atleast 0.70, or at least 0.90, at 1.2 mm thickness after aging for 7 daysat 70° C., or had a pFTP(V0) of at least 0.60 at 1.2 mm thickness afteraging for 7 days at 70° C.

Additional batch compositions included a cross-linkable polycarbonateresin comprising from 2 to 4 wt % of end-caps derived from4-hydroxybenzophenone, and having a weight average molecular weight from15,000 to 30,000 as measured by GPC using a UV detector andpolycarbonate standards; had a 4-hydroxybenzophenone content from 1.3 wt% to 3.8 wt % in the composition; had a melt flow rate (MFR) of 7 to 20g/10 min measured at 300° C./1.2 kg/360 sec dwell; and could be used forform articles/parts that had a % T of 85% or greater at 3.2 mm thicknessprior to UV exposure; and after exposure to at least 35 J/cm² of UVAradiation has a delta YI of 8 or less at 3.2 mm thickness measured atleast 48 hours after exposure, a % T of 75% or greater, a % retention of85% or greater at 3.2 mm thickness in a tensile elongation at break testusing the ASTM D638 Type I method at 50 mm/min after exposure to acetoneunder 1.0% strain at 23° C., and a pFTP(V1) of at least 0.90 at 1.2 mmthickness after aging for 7 days at 70° C. In addition to theseproperties, the composition could have a melt flow rate (MFR) of 7 to 10g/10 min, or of 10 to 15 g/10 min, or of 15 to 20 g/10 min, or of 7 to15 g/10 min.

Predictive Equations

In order to help design polycarbonates that would consistently (A) passthe UL 94 V1 test after 7 days of aging at 70° C. and (B) provide highpercentage of retention of tensile elongation following exposure toacetone while (C) minimizing the color shift due to UV exposure, apredictive tool was needed. Based on the 50 samples in the large scalestudy described above in Tables 22A-H, a polynomial equation thatprovided a model fit to each desired response (i.e. p(FTP), tensileelongation retention, and delta YI) was obtained (Design-Expert® version7.0.3 from Stat-Ease, Inc.). The parameters in the equations included(1) the melt flow rate of the polycarbonate blend, MF, in g/10 min; (2)the UV dosage, D, in J/cm² for UVA radiation; (3) the weight averagemolecular weight, MW, in Daltons, of the blend; and (4) thehydroxybenzophenone level, HBP, in weight percent, of the blend. Someresponses were affected by (5) the usage of a filtered versusnon-filtered UV source, resulting in two separate equations based onthis parameter. The five resulting equations are shown below. In theseequations, “Ln” refers to the natural log (base e), and “sqrt” indicatesthe square root.

$\begin{matrix}{{{Sqrt}\left( {{p({FTP})} + 0.01} \right)} = {{- 0.37308} + \left( {0.05345 \times D} \right) + \left( {0.22797 \times {HBP}} \right) - \left( {2.06081 \times 10^{- 6} \times {MW}} \right) - \left( {0.092440 \times {MF}} \right) + \left( {2.81460 \times 10^{- 6} \times {MW} \times {MF}} \right) - \left( {0.000583 \times D^{2}} \right)}} & {{Eqn}\mspace{14mu} 1}\end{matrix}$UV Source Unfiltered (D-Bulb):

$\begin{matrix}{{{Ln}\left( {{Delta}\mspace{14mu}{YI}} \right)} = {1.01074 + \left( {0.08387 \times D} \right) - \left( {0.041908 \times {MF}} \right) - \left( {0.00077 \times D^{2}} \right) + \left( {2.41546 \times 10^{- 3} \times {MF}^{2}} \right)}} & {{Eqn}\mspace{14mu} 2} \\{{{Sqrt}\left( {{{Elongation}\mspace{14mu}{Retention}} + 1.04} \right)} = {{- 29.23264} + \left( {0.62157 \times D} \right) + \left( {1.57655 \times {HBP}} \right) + \left( {1.27584 \times 10^{- 3} \times {MW}} \right) - \left( {1.63711 \times 10^{- 5} \times D \times {MW}} \right) - \left( {0.002382 \times D^{2}} \right)}} & {{Eqn}\mspace{14mu} 3}\end{matrix}$UV Source Filtered

$\begin{matrix}{{{Ln}\left( {{Delta}\mspace{14mu}{YI}} \right)} = {0.44154 + \left( {0.07712 \times D} \right) - \left( {0.041908 \times {MF}} \right) - \left( {0.00077 \times D^{2}} \right) + \left( {2.41546 \times 10^{- 3} \times {MF}^{2}} \right)}} & {{Eqn}\mspace{14mu} 4} \\{{{Sqrt}\left( {{{Elongation}\mspace{14mu}{Retention}} + 1.04} \right)} = {{- 30.25285} + \left( {0.62157 \times D} \right) + \left( {1.57655 \times {HBP}} \right) + \left( {1.27584 \times 10^{- 3} \times {MW}} \right) - \left( {1.63711 \times 10^{- 5} \times D \times {MW}} \right) - \left( {0.002382 \times D^{2}} \right)}} & {{Eqn}\mspace{14mu} 5}\end{matrix}$

The characteristics for each model equation are shown in Table 23:

TABLE 23 Elongation p(FTP) Retention Delta YI Adjusted R-Squared 0.640.84 0.97 Predicted R-Squared 0.56 0.81 0.96 Adequate Precision 12.7724.61 48.54

The predicted R-Squared value shows reasonable agreement with theAdjusted R-Squared value for each equation. Adequate Precision measuresthe signal to noise ratio. A ratio greater than 4 is generallydesirable. Here, the ratios range from 12.77 to 48.54, which indicatesan adequate signal and thus these equations can be used to navigate thedesign space.

All three equations show relatively good predictive ability. The DeltaYI equation is particularly powerful in the design space producingcalculated values typically within 10% of the measured response. Aproposed design space could then be identified by combining the responseequations.

FIG. 24 is a chart showing the model equation for the pFTP(V1) rating(Eqn 1), where the MFR has been held constant at 7.65. The x-axis is theUV dose, and the y-axis is the HBP level. The resulting curves show thepredicted pFTP(V1) rating for various combinations of UV dose and HBPlevel. The pFTP cannot be greater than 1, so the dark space in theupper-right area of the chart shows combinations that should not betried. Generally, the light area in the curves between 0.674279 and1.00229 is the desired design space.

FIG. 25 is another chart showing the model equation for the pFTP(V1)rating (Eqn 1), where the MFR has been held constant at 19.9. The axesare the same as FIG. 24, but the design space here is different.Generally speaking, higher UV doses and higher HBP levels are needed toobtain the same pFTP(V1) rating.

FIG. 26 is a chart showing the model equation for the retention oftensile elongation using a filtered bulb (Eqn 3), where the HBP level isheld constant at 1.26 wt %. The x-axis is the UV dose, and the y-axis isthe MW. The curves show the predicted percentage of retention of tensileelongation. The desired area here is in the upper right of the chart.

FIG. 27 is another chart showing the model equation for the retention oftensile elongation using a filtered bulb (Eqn 3), where the HBP level isheld constant at 3.79 wt %. The axes are the same as FIG. 26, but thearea where the desired elongation retention is met is much largercompared to that of FIG. 26.

FIG. 28 is a chart that illustrates the combination of the three modelequations to find a design space. The MF is set at 7 and the MW is setat 23,000, and the model equations using a filtered UV light source areused. Thus, Eqns 1, 4, and 5 are used. The x-axis is the UV dose, andthe y-axis is the HBP level. The equations can then be used to determinethe design space where the % retention of elongation will be greaterthan 85%, the delta YI will be less than 8, and the pFTP(V1) rating willbe greater than 0.7. The area to the left of the vertical line(approximately dose=6.5) denotes the space where the delta YI of lessthan 8 can be obtained. The area above the curved line denotes the spacewhere the % retention of elongation is greater than 85%. Theirintersection (i.e. the lighter area in the center) provides the designspace (combination of HBP level and UV dose) needed to obtain thesethree desired properties. It should also be noted that in FIGS. 24-28,the UV dosage on the x-axis is listed as the number of passes under theUV lamp, which equates to 12-60 J/cm² UVA; the values on the x-axis arenot the dosage itself.

Eqn 1 is an equation for the probability of a first time pass on theUL94 V1 test for an article made of a given polycarbonateblend/composition at 1.2 mm after UV exposure and 7 days of aging at 70°C. Eqn 2 and Eqn 3 apply when the UV exposure is performed with anunfiltered D-bulb, which provides at least 12 J/cm² of UVA radiation andat least 0.45 J/cm² of UVC radiation. Eqn 4 and Eqn 5 apply when the UVexposure is performed with a filtered D-bulb, which provides at least 12J/cm² of UVA radiation and no detectable J/cm² of UVC radiation. Theoutput of the UV light source is measured using an EIT PowerPuck.

These five equations can be combined in any manner to design polymericcompositions, UV dosages, and UV sources to obtain any combination ofdesired properties.

Eqn 1 can be used alone to obtain articles that have a high pFTP(V1). Itshould be noted that this equation does not depend on the UV lightsource (unfiltered or filtered). In specific embodiments, the targetedpFTP(V1) is 0.7 or greater.

Eqn 2 can be used alone to obtain articles that have a low delta YI whenexposed to an unfiltered D-bulb. In specific embodiments, the targeteddelta YI is 15 or less, or 10 or less, or 8 or less, or 5 or less.

Eqn 3 can be used alone to obtain articles that have a high percentageof retention of tensile elongation when exposed to an unfiltered D-bulb.In specific embodiments, the targeted percentage is 85% or greater, or90% or greater.

Eqn 4 can be used alone to obtain articles that have a low delta YI whenexposed to a filtered D-bulb. In specific embodiments, In specificembodiments, the targeted delta YI is 15 or less, or 10 or less, or 8 orless, or 5 or less.

Eqn 5 can be used alone to obtain articles that have a high percentageof retention of tensile elongation when exposed to a filtered D-bulb. Inspecific embodiments, the targeted percentage of retention of tensileelongation is 85% or greater, or 90% or greater.

Eqn 1 and Eqn 2 can be combined to obtain articles that have a highpFTP(V1) and a low delta YI when exposed to an unfiltered D-bulb. Inspecific embodiments, the targeted pFTP(V1) is 0.7 or greater; and thetargeted delta YI is 15 or less, or 10 or less, or 8 or less, or 5 orless. Any of these four combinations is specifically contemplated.

Eqn 1 and Eqn 3 can be combined to obtain articles that have a highpFTP(V1) and a high percentage of retention of tensile elongation whenexposed to an unfiltered D-bulb. In specific embodiments, the targetedpFTP(V1) is 0.7 or greater; and the targeted percentage of retention oftensile elongation is 85% or greater, or 90% or greater. Either of thesetwo combinations is specifically contemplated.

Eqn 1 and Eqn 4 can be combined to obtain articles that have a highpFTP(V1) and a low delta YI when exposed to a filtered D-bulb. Inspecific embodiments, the targeted pFTP(V1) is 0.7 or greater; and thetargeted delta YI is 15 or less, or 10 or less, or 8 or less, or 5 orless. Any of these four combinations is specifically contemplated.

Eqn 1 and Eqn 5 can be combined to obtain articles that have a highpFTP(V1) and a high percentage of retention of tensile elongation whenexposed to a filtered D-bulb. In specific embodiments, the targetedpFTP(V1) is 0.7 or greater; and the targeted percentage of retention oftensile elongation is 85% or greater, or 90% or greater. Either of thesetwo combinations is specifically contemplated.

Eqn 2 and Eqn 3 can be combined to obtain articles that have a low deltaYI and a high percentage of retention of tensile elongation when exposedto an unfiltered D-bulb. In specific embodiments, the targeted delta YIis 15 or less, or 10 or less, or 8 or less, or 5 or less; and thetargeted percentage of retention of tensile elongation is 85% orgreater, or 90% or greater. Any of these eight combinations isspecifically contemplated.

Eqn 4 and Eqn 5 can be combined to obtain articles that have a low deltaYI and a high percentage of retention of tensile elongation when exposedto a filtered D-bulb. In specific embodiments, the targeted delta YI is15 or less, or 10 or less, or 8 or less, or 5 or less; and the targetedpercentage of retention of tensile elongation is 85% or greater, or 90%or greater. Any of these eight combinations is specificallycontemplated.

Eqn 1, Eqn 2, and Eqn 3 can be combined to obtain articles that have ahigh pFTP(V1), a low delta YI, and a high percentage of retention oftensile elongation when exposed to an unfiltered D-bulb. In specificembodiments, the targeted pFTP(V1) is 0.7 or greater; the targeted deltaYI is 15 or less, or 10 or less, or 8 or less, or 5 or less; and thetargeted percentage of retention of tensile elongation is 85% orgreater, or 90% or greater. Any of these eight combinations isspecifically contemplated.

Eqn 1, Eqn 4, and Eqn 5 can be combined to obtain articles that have ahigh pFTP(V1), a low delta YI and a high percentage of retention oftensile elongation when exposed to a filtered D-bulb. In specificembodiments, the targeted pFTP(V1) is 0.7 or greater; the targeted deltaYI is 15 or less, or 10 or less, or 8 or less, or 5 or less; and thetargeted percentage of retention of tensile elongation is 85% orgreater, or 90% or greater. Any of these eight combinations isspecifically contemplated.

The five equations use the melt flow rate of the polycarbonate blend(MF), the UV dosage (D), the weight average molecular weight of theblend (MW), and the hydroxybenzophenone level of the blend (HBP). Inparticular embodiments, MF can be from 7 to 20 g/10 min, as measured at300° C./1.2 kg/360 sec dwell. In some more specific embodiments, MF canbe 7 to 10, 10 to 15, or 15 to 20 g/10 min. In particular embodiments, Dcan be at least 12 J/cm² of UVA radiation. In particular embodiments, MWcan be 15,000 to 30,000 Daltons. It is noted that this is the MW of theblend, not of the cross-linkable polycarbonate resin alone. Inparticular embodiments, HBP can be from 1.2 wt % to 4 wt % of the blend.Again, this is the 4-hydroxybenzophenone content of the blend, not ofthe cross-linkable polycarbonate resin by itself. Various combinationsof these properties can be indicated by various combinations of the fiveequations. Typically, one or two of these properties is held constant,and using the equations defines suitable ranges for the other two orthree properties.

Formed Articles

A molded mouse cover was made from an XPC-D resin which was abisphenol-A polymer with 4-hydroxybenzophenone endcaps present in anamount of 2.5 mole %, with no p-cumylphenol endcap, and having an Mw of22,000. The XPC-D resin was blended with 0.06 phr phosphite stabilizer.The composition had an MVR (300° C./1.2 kg, 360 sec dwell) of 8.5 cc/10min. The composition was injection molded to obtain the molded mousecover.

The molded mouse cover was then passed 6 times through the Loctitesystem, with the top facing the UV lamp. A t-bar was also exposed as acontrol for comparison.

After UV exposure, the gel thickness of the mouse cover was 18.64microns at the front, 24.10 microns at the middle, and 16.55 microns atthe back, with an average thickness of 19.76 microns for the entirepart. For comparison, the gel thickness for the t-bar was 29.91 microns.The presence of a gel layer indicated that crosslinking had occurred.The YI of the mouse cover before UV exposure was 0.18, and 48 hoursafter UV exposure was 3.84.

Fibers were also made using the composition containing XPC-D andphosphite stabilizer. A Fiberlab L1000 device (from Fiberio) was used.10 wt % of the composition was dissolved in methylene chloride to form asolution, which was placed in a liquid reservoir. This liquid reservoirwas spun on a vertical axis, pushing the liquid state material to theouter wall where orifices were present. The centrifugal and hydrostaticforces initiate a liquid jet, and external shear forces promote coolingand solvent evaporation, creating the fiber.

Two sets of fibers were made. At 12,000 rpm and an orifice diameter of159 microns, fibers were made having an average fiber diameter of 12.4microns. At 12,000 rpm and an orifice diameter of 210 microns, fiberswere made having an average fiber diameter of 14.5 microns. Some fiberswere then exposed to UV light in the Loctite system (approximately 36J/cm² of UVA).

Exposed and un-exposed fibers were then placed in methylene chloride.Un-exposed fibers dissolved, while undissolved material remained for theexposed fibers, indicating a gel had been formed and crosslinking hadoccurred.

The present disclosure has been described with reference to exemplaryembodiments. Obviously, modifications and alterations will occur toothers upon reading and understanding the preceding detaileddescription. It is intended that the present disclosure be construed asincluding all such modifications and alterations insofar as they comewithin the scope of the appended claims or the equivalents thereof.

The invention claimed is:
 1. An article molded from a polycarbonate composition, wherein the polycarbonate composition comprises: a cross-linkable polycarbonate resin comprising from 2 to 4 wt % of endcaps derived from a monohydroxybenzophenone, and having a weight average molecular weight from 15,000 to 30,000 as measured by GPC using a UV detector and polycarbonate standards; optionally one or more additional polycarbonate base resins different from the cross-linkable polycarbonate resin; optionally a flame retardant; and optionally a colorant, a UV stabilizer, a thermal stabilizer, or a mold release agent; wherein the polycarbonate composition has a monohydroxybenzophenone derived endcap content from 1.3 wt % to 3.8 wt %, and a melt flow rate (MFR) of 7 to 20 g/10 min measured at 300° C./1.2 kg/360 sec dwell, and wherein a molded part formed from the polycarbonate composition has a % T of 85% or greater at 3.2 mm thickness; and wherein a part molded from the polycarbonate composition and exposed to at least 35 J/cm² of UVA radiation has a change in yellowness index (delta Y) of 8 or less at 3.2 mm thickness measured at least 48 hours after exposure, a light transmission (% T) of 75% or greater, a % retention of 85% or greater at 3.2 mm thickness in a tensile elongation at break test using the ASTM D638 Type I method at 50 mm/min after exposure to acetone under 1.0% strain at 23° C., and a pFTP(V1) of at least 0.90 at 1.2 mm thickness after aging for 7 days at 70° C.; and wherein the cross-linkable polycarbonate resin has the structure of Formula (I):

wherein R¹ and R² are independently halogen, C₁₋₆ alkyl, C₃₋₈ cycloalkyl, aryl, or arylalkyl; x is an integer from 0 to 4; y is an integer from 0 to 5; n′ is an integer from 29 to 65; and the repeating unit W is derived from: (i) a monomer having the structure: HO-A₁-Y₁-A₂-OH wherein each of A₁ and A₂ comprise a monocyclic divalent arylene group, and Y₁ is a bridging group having one or more atoms; or (ii) a monomer having the structure:

each R^(k) is independently halogen, a C₁₋₁₀ hydrocarbon group, or a halogen substituted C₁₋₁₀ hydrocarbon group; and n is 0 to
 4. 2. The article of claim 1, wherein the polycarbonate composition has a melt flow rate (MFR) of 7 to 10 g/10 min.
 3. The article of claim 1, wherein the polycarbonate composition has a melt flow rate (MFR) of 10 to 15 g/10 min.
 4. The article of claim 1, wherein the polycarbonate composition has a melt flow rate (MFR) of 15 to 20 g/10 min.
 5. The article of claim 1, wherein the cross-linkable polycarbonate resin has the structure of Formula (II):

wherein n′ ranges from 29 to
 65. 6. The article of claim 1, wherein the cross-linkable polycarbonate resin has a polydispersity index (PDI) of between 3.0 and 7.3 as measured by GPC using a UV detector and polycarbonate standards.
 7. The article of claim 6, wherein the ratio of the polydispersity index (PDI) measured using a UV detector to the PDI measured using an RI detector is 1.8 or less, when using a GPC method and polycarbonate molecular weight standards.
 8. The article of claim 1, wherein the article is a film, a sheet, a layer of a multilayer film, or a layer of a multilayer sheet.
 9. The article of claim 1, wherein the article is at least one of an automotive bumper, an automotive exterior component, an automobile mirror housing, an automobile grille, an automobile pillar, an automobile wheel cover, an automobile instrument panel or trim, an automobile glove box, an automobile door hardware or other interior trim, an automobile exterior light, an automobile part within the engine compartment, an agricultural tractor or device part, a construction equipment vehicle or device part, a construction or agricultural equipment grille, a marine or personal water craft part, an all terrain vehicle or all terrain vehicle part, plumbing equipment, a valve or pump, an air conditioning heating or cooling part, a furnace or heat pump part, a computer part, a computer router, a desk top printer, a large office/industrial printer, an electronics part, a projector part, an electronic display part, a copier part, a scanner part, an electronic printer toner cartridge, a hair drier, an iron, a coffee maker, a toaster, a washing machine or washing machine part, a microwave, an oven, a power tool, an electric component, an electric enclosure, a lighting part, a dental instrument, a medical instrument, a medical or dental lighting part, an aircraft part, a train or rail part, a seating component, a sidewall, a ceiling part, cookware, a medical instrument tray, an animal cage, fibers, a laser welded medical device, fiber optics, a lense (auto and non-auto), a cell phone part, a greenhouse component, a sun room component, a fire helmet, a safety shield, safety glasses, a gas pump part, a humidifier housing, a thermostat control housing, an air conditioner drain pan, an outdoor cabinet, a telecom enclosure or infrastructure, a Simple Network Detection System (SNIDS) device, a network interface device, a smoke detector, a component or device in a plenum space, a medical scanner, X-ray equipment, a construction or agricultural equipment, a hand held electronic device enclosure or part, a wearable electronic device, a hand held tool enclosure or part, a smart phone enclosure or part, a mouse cover, and a turbine blade.
 10. The article of claim 1, wherein the article is at least one of a computer housing, a computer housing or business machine housing or part, a housing or part for monitors, a computer router, a copier, a desk top printer, a large office/industrial printer, a handheld electronic device housing, a housing for a hand-held device, a component for a light fixture, a humidifier housing, a thermostat control housing, an air conditioner drain pan, an outdoor cabinet, a telecom enclosure or infrastructure, a Simple Network Intrusion Detection System (SNIDS) device, a network interface device, a smoke detector, a component or device in a plenum space, a component for a medical application or a device, an electrical box or enclosure, and an electrical connector.
 11. The article of claim 1, wherein the article is formed by injection molding, overmolding, co-injection molding, extrusion, multilayer extrusion, rotational molding, blow molding, or thermoforming. 